Therapeutic potential of Ficus benghalensis in thromboembolic disorders

Objective Ficus benghalensis L. (FB) is a popular plant described in the Indian system of medicine. Traditionally, it is indicated in the treatment of diseases like diabetes mellitus, dysentery, leucorrhoea, menorrhagia, skin disease, rheumatism, inflammatory diseases, blood disorders. This paper accentuates the anti-thrombotic action of FB based on the properties like anti-coagulant, platelet-antiaggregatory, anti-atherogenic hypotensive, hypolipidemic, anti-oxidant, anti-inflammatory and immunomodulatory. Methods All the available data pertaining to FB has been searched in the scientific databases, including PubMed, Google Scholar, ScienceDirect and Scopus. Results FB is a rich lode of organic compounds such as phenols, flavonoids, alkaloids, tannins, terpenoids and steroids. The various studies show that these phytochemical constituents exhibit wide range of anti-thrombotic actions such as anticoagulant, platelet anti-aggregatory, anti-atherogenic, hypolipidemic, hypotensive, anti-inflammatory, and antioxidant. Conclusion Various studies (in vitro and in vivo) confirm the potential anti-thrombotic benefit of FB due to the presence of chemical structures that have proven to be effective in thromboembolic conditions. These evidences may benefit in new drug development to treat varied thromboembolic conditions which will not only be cost effective but may allay the fear of side effects.


Introduction
Cardiovascular diseases contribute to 32% of annual deaths worldwide [1] and distinctively, thromboembolic conditions account for 1 in 4 deaths.Estimates for the global incidence rate (IR) confirms 114.3 ischemic stroke, 139.3 for myocardial infarction, 1518.7 for ischemic heart disease, 77.5 for atrial fibrillation in males and 59.5 in females, and 115 to 269 for venous thromboembolism per 100000 population [2].
Thrombosis is the formation of a blood clot in the blood vessels, limiting the natural flow of blood and resulting in clinical sequelae.Embolus is a dislodged intravascular mass that can be solid, liquid or gas that travels with the blood from its point of origin to a distant site, leading to infarction or tissue dysfunction.The majority of the emboli are formed from dislodged thrombi; hence, it is known as thromboembolism [3].Thromboembolic conditions can be classified into two categories: arterial thromboembolism (ATE), which majorly encompasses ischemic heart disease, chronic peripheral arterial disease, and ischemic stroke, and venous thromboembolism (VTE), including pulmonary embolism and deep vein thrombosis.The etiology of thromboembolism is multifactorial.Obesity, progressing age, high blood pressure, diabetes, high cholesterol level, sedentary lifestyle, cigarette smoking, mitral stenosis, and atrial fibrillation are the primary risk factors for ATE, whereas chronic illness, bed confinement, trauma, and oestrogen-based therapy are the major risk factors for VTE [4].
Thrombus formation and propagation depends on the damage to the vascular endothelial cells, the increase in blood coagulability, and change in blood flow.Arterial thrombosis mostly begins with the deposition of lipid plaques in the lumen of the artery, evoking chronic inflammatory cells and activating the platelets.These fatty plaques then evolve into fibrous plaques, which could disrupt into unstable atherosclerotic plaques, which in turn release additional pro-coagulating factors that activates the platelets, causing adhesion and accumulation, leading to clot formation [5].
Drugs play a crucial role in the prevention and treatment of thromboembolism.Anticoagulant medications that target pro-coagulant factors are the cornerstone to treat venous thromboembolism, whereas antiplatelet medications used as monotherapy or dual-antiplatelet therapy are typically used to treat arterial thrombosis.Anti platelet drugs namely COX inhibitors, ADP receptor antagonists, Proteaseactivated-receptor-1 inhibitors, and αIIbβ3-Integrin inhibitors, as well as anticoagulant agents including vitamin K antagonist, un-fractioned heparins, Xa factor inhibitors, thrombin inhibitors, and coumarin derivatives are the current standard care for the treatment [6].However, anticoagulants are limited by certain factors such as unpredictability regarding estimation of drug dosage, safe drug levels for major surgery, management of haemorrhage and renal dependence as well as multi dose plans [7].
The Indian subcontinent is a rich source of medicinal plants that have been used in health care since ancient time.More than 70% of the Indian population still uses traditional medicine for a variety of reasons, including sociocultural factors; perceived safety of herbal drugs; easy availability; rising costs of modern drugs; subpar healthcare facilities; and adverse effects of modern drugs and non-compliance.Also, the growing importance of medicinal plants can be appreciated from various economic vantage points as well.The Indian Banyan Tree, known as "Bargad" in Hindi, is a large perineal tree indigenous to the Indian subcontinent.It is spread all across the country and is known as Ficus benghalensis (FB).Traditionally, each part of the plant is found to have various therapeutic uses with vast commercial potential.Phytochemical analysis of various extracts of plant parts revealed the presence of amino acids, vitamins, phenols, terpenoids, phytosterols, flavonoids, alkaloids, anthraquinones, as well as cardiac glycosides [8][9][10].Although not much description is available in the ancient Ayurvedic literature narrating its use as anti-thromboembolic agent, however, pharmacological properties such as in-vitro anticoagulant property, in-vitro platelet anti-aggregatory effect, in-vivo blood pressure lowering effect, direct antiatherogenic effect, and hypolipidemic effect reported in various studies reflect its anti-thromboembolic activity [11][12][13][14][15].In addition to this, properties including antioxidant effect, anti-inflammatory effect and free radical scavenging activity, have been delineated in several studies [16,17].Hence, in view of the above-mentioned favourable pharmacological profile of FB, the present review focuses on exploring the prospect of its rational use for treating various thromboembolic conditions.

Methodology
Database searches using Google Scholar, PubMed, and Science Direct were conducted until 15th May 2023 to include up to date documented information in the present review article.The search was limited to English language papers.For data mining, the following MESH words were used in the databases mentioned above: FB traditional use, FB ethnomedicinal uses, FB phytochemical constituent, FB pharmacological studies, FB Phenolic, Terpenoids, Tannins, Glycosides, phytosterols compounds, FB pharmacognosy, FB in vitro study, FB in-vivo study, FB antioxidant, FB anti-inflammatory anti-aggregatory/antiplatelet, FB anti-atherogenic, FB hypolipidemic, FB hypocholesteraemia, FB anticoagulant, FB hypotensive, FB toxicity studies.In almost all cases, the original articles were obtained and the relevant data was extracted.The chemical structures were made using the ChemDraw software.

Ethnomedicinal consideration
FB, popularly known as Nyagrodha or Vatta in Ayurveda, is one of the most glorified sacred trees with an immense ethnobotanical history.It possesses vast medicinal properties and is an important ingredient in many Ayurvedic formulations.Traditionally, different plant parts have been used in many disease conditions like diabetes mellitus, dysentery, diarrhea, leucorrhoea, menorrhagia, skin disease, rheumatism, inflammatory diseases, blood disorders etc. (Table 1) [11,15,[18][19][20].

Habitat
FB belongs to the Moraceae family and grows well in tropical as well as semi-tropical regions.It is indigenous to Asian countries including India, Burma, China, Thailand, Malaysia, and other Southeast Asian countries.

Morphology
It is a giant evergreen tree standing up to 30 m high above the ground level with numerous aerial roots descending down the branches.The bark is smooth, thick, and green in colour in juvenile stage whereas it is greyish-white when mature.The fresh cut area of bark is pinkish in colour and secretes milky latex.Leaves are simple, with an alternate arrangement.They are leathery, ovate to elliptic, 4-6 inches long with reticular venation and a rounded or subcordate base.Unripe fruits are dark red achenes, 15 to 20 mm in diameter, globose, fleshy and fixed in axillary pairs and they turn dark purple when ripe.It has very small (~18 mm) and distinct male, female, and imperfect female flowers with male ones packed adjacent to the receptacle mouth while female flowers have a shorter perianth and a long style.

Phytochemical constituents
Phytochemical investigations of FB show a variety of bioactive chemical constituents that are responsible for its broad pharmacological activities related to the prevention and treatment of thromboembolism, either directly or indirectly.It contains bioactive compounds from diverse classes including alkaloids, phenols, cardiac glycosides flavonoids, tannins, saponins, steroids, triterpenes, xanthoproteins, and coumarins (Table 2) [18].

Phenolic compounds
FB contains phenolic compounds including flavonoids such as Quercetin, Naringenin, Kaempferol, Quercetin-3-galactoside, etc. that have been isolated from its various parts [8,21].Quantitative analysis revealed a significant amount of flavonoid content in the aqueous fraction (0.5148 ± 0.02 mg GAE/g dE) and hydroalcoholic extract (97mg/gm ± 5.10) of stem bark [18,22].Quercetin-3-galactoside and rutin are found to be present in the leaves [23].The biological and oxidative properties of flavonoids are responsible for their

Table 1
Traditional uses of different parts of FB in different disorders.cardioprotective, anti-inflammatory, and anti-oxidative activities.There is ample acceptable evidence present that indicates the role of bioflavonoids, in free radical scavenging activity, enhancement of endothelial-derived nitric oxide activity as well as prevention of Low-Density Lipoprotein-Cholesterol (LDL C) oxidation [24], endothelial activation inhibition [25], and inhibition of platelet aggregation [26], and hence they probably reduce the risk of thrombosis.
A few handful of research have been conducted to elicit the antithrombotic characteristics of certain flavonoids which are found to be present in FB as well [27].The anticoagulant and antithrombotic effect of quercetin and quercetin-3-O-β-D-glucoside (isoquercetin) was inferred through the inhibition of production of fibrin clots and blood clotting by impeding the enzymatic activity of FXa and thrombin and reducing epinephrine and collagen-induced platelet activation.Another flavonoid named Kaempferol showed anti-thrombotic action in collagen/epinephrine-and thrombin-induced acute thromboembolism models and FeCl 3 -induced carotid arterial thrombus models [28].Furthermore, the antiatherogenic effects of leucopelargonin and leucocyanin were investigated in cholesterol rats and results showed a remarkable decrease in the atherogenic index, faecal excretion of bile acids, hepatic bile acid level, neutral sterols, lipogenic enzyme activities as well as HMG-CoA reductase in the liver significantly [13].Hence, due to the presence of these flavonoids, FB may be clinically useful to prevent or treat thrombotic conditions.
Lupeol identified and isolated from the dry leaves of Elephantopus scaber Linn.exhibited platelet aggregation activity at different concentrations [31].Epifriedelanol and friedelin obtained from crude methanolic extract of leaves of Cissus trifoliata (L.) showed significant thrombolytic activity by in-vitro assay against distilled water and streptokinase (30,000 IU) as negative and positive thrombolytic controls respectively [32].
Few flavonoids and terpenoids isolated from FB are displayed in Fig. 1.

Tannins
Tannins in general exhibit anti-platelet activity, oxidative stress inhibition, maintain hemostasis and prevent nitric oxide (NO), prostacyclin (PGI2), and tissue-type plasminogen activator (t-PA) mediated disruption of cell membranes.Quantitative analysis showed a significant amount of tannin content in the micro-oven-dried fruit of FB (38.27 ± 06.03 mg GAE/g extract) [21].FB bark also contains high levels of tannins [33].Another study showed the presence of tannin in different solvents, while the highest was found in the aqueous fraction of the bark (3.787 ± 0.043 mg GAE/g dE) [18].The methyl alcohol extract of leaves was reported to possess antioxidant capacity with an abundant quantity of tannins [34].
Catechin, epigallocatechin, and Gallic acid are the major tannins present in FB.Studies suggested that green tea catechins and epigallocatechin gallate extracted from green tea showed significant antithrombotic actions.It inhibited pulmonary thrombosis-related death in mice with a substantial increase in the bleeding time of mouse tail of conscious mice and suppressed ex-vivo rat platelet aggregation mediated by adenosine diphosphate and collagen in a dose-related manner.It also restrained ADP, collagen, epinephrine, and calcium ionophore A23187 induced human platelet aggregation in-vitro, in a dose-related manner [35].Another study demonstrated the anti-platelet activity of green tea catechin due to inhibition of TXA2 formation by inhibiting arachidonic acid liberation and TXA2 synthase [36].In addition to this, Gallic acid was found to suppress platelet aggregation, platelet-leukocyte aggregation, and P-selectin expression in a directly proportional manner to concentration.It further prevented the elevation of intracellular calcium and attenuated phosphorylation of PKCα/p38 MAPK and Akt/GSK3β on platelets stimulated by the stimulants ADP or U46619 [37].These findings suggest a potential medicinal application of tannins thrombotic conditions.

Table 2
Phytochemical constituents of various parts of FB.

Coumarins
The fruits, seeds, leaves, and bark of FB are a rich source of coumarins (Fig. 2) [9,38].Bergapten (5-methoxypsoralen) and psoralen are the furocoumarin compounds that are abundantly found in the seeds of FB [39].In addition to these, the leaves contain one furanocoumarin derivative, namely rhein [9].Coumarins are competitive inhibitors of Vitamin K in the biosynthesis of prothrombin.Also, they exert anti-inflammatory, anticoagulant, antioxidant, and enzyme inhibition effects [40].According to in-vitro assay results, bergapten and psoralen extracted from Angelica shikokiana, were shown to exhibit considerable antiplatelet action against ADP and arachidonic acid-induced platelet aggregations in a concentration-dependent manner [41].

Glycosides
FB is one of the rich sources of glycosides like 20-tetratriaconthene-2-one, 6-heptatriacontene-10-one, pentatriacontan-5-one, and beta sitosterol-alpha-D-glucose.The crude methanolic extract of bark confirmed the presence of cardiac glycoside, while the methyl alcohol, hexane, and ethyl acetate extracts from the aerial roots showed the presence of both cardiac and steroidal glycosides [10,18].Also, the presence of a fatty acid glycoside (2-O-a-L-rhamnopyranosyl-hexacosanoate-b-D-glucopyranosyl ester) was detected in the methanolic extract of leaves.That exhibited antioxidant activity and has potential for inhibition of acetylcholinesterase [42].Glycoside of leucopelargonidin isolated from the bark of FB exhibited a remarkable anti-lipidemic effect via enhanced faecal excretion of sterols and bile acids in moderately diabetic rats (Fig. 3) [43].

Amino acids
FB has been reported to have one of the highest sources of amino acid present in fruit protein [44].Concentrated aqueous extract of the seeds and fresh fruits contained various amino acids such as cysteine, glutamine, methionine, tryptophan, arginine, citrulline, and hydroxyproline.
Glutathione, an important antioxidant, has also been isolated from the fruit of FB [8].

Fatty acid
Vernolic, malvalic, and sterculic acids have been found to be present in FB seed oil together with lauric, myristic, palmitic, stearic, oleic, and linolenic acids [8,45].Linolenic acid is found to exhibit antithrombotic action by reducing P-selectin secretion, GP IIb/IIIa expression, and by reducing the expression level of PI3K and Akt [46].

Phytosterol
Lanostadienylglucosyl cetoleate and bensisteroic acid ester were found to be present in methanolic extract of the stem bark of FB [8,45,47].Evidence from various studies shows that phytosterols reduce atherosclerosis by means of both useful alterations in High Density Lipoprotein (HDL) and LDL metabolism and inflammatory pathways [48].Phytosterols have also been noted to exhibit cholesterol-lowering effect, high LDL receptor expression, and lower circulation LDLC concentration [49].
Different plant parts and their distinguished extracts showed various components which are indicating the effect of FB towards the antithromboembolic effect as shown in Table 2.

Pharmacological studies
FB has been vastly studied for multiple pharmacological effects which are concerned with both prophylaxis and treatment of the thromboembolic disorder (Fig. 4).

Anticoagulant activity
The fractionated crude methanol extracts of leaves of FB using liquidliquid partition with ethyl acetate, n-hexane, and chloroform in healthy human blood plasma, showed anticoagulant action, with delayed "prothrombin time (PT)" (21.7 ± 1.2 s) compared to the normal control (13.3 ± 0.6 s).The prothrombin values of n-hexane ranged from 17.3 ± 0.9 to 21.0 ± 1.0 s, chloroform, and ethyl acetate ranged between 17.7 ± 0.7 to 22.0 ± 1.1 and 17.8 ± 0.9 to 24.0 ± 1.5 s, respectively.It also showed significantly higher activated partial thromboplastin time (APTT) than normal and varied from 51.7 ± 2.4 to 72.3 ± 5.4, 49.7 ± 6.1 to 71.7 ± 5.5, and 47.7 ± 3.3 to 69.7 ± 2.9 s, respectively, for the nhexane, chloroform, and ethyl acetate fractions [12].This result clearly shows that FB has anti-coagulant properties, which may be supported by its notable phenolic and flavonoid content.

Platelet anti-aggregation activity
Water soluble fractions of ethanolic extracts of leaves of FB in concentrations of 8 mg/ml exhibited significant platelet anti-aggregatory activity against ADP-induced platelet aggregation in an in-vitro study.It inhibited platelet aggregation by 77.26 ± 0.7 % (8 mg/ml), and the IC50 value was obtained at 4.87 ± 0.38 mg/ml [14].

Antiatherogenic activity
Leucopelargonin and leucocyanin isolated from the bark of FB, along with quercetin in a dose of 100 mg/kg/day significantly decreased the liver-to-body weights (7-9%) in cholesterol-fed male SD rats.The activities of HMG-CoA reductase and lipogenic enzymes in the liver, lipoprotein lipase in the heart, adipose tissue, and plasma LCAT, as well as ester cholesterol in the liver, all declined markedly.Additionally, the hepatic level of bile acids increased, so as the faecal excretion of bile acids and neutral sterols, while the action of glucose-6-phosphate dehydrogenase decreased.The leucopelargonin derivative and quercetin showed a slightly better and more significant effect than the leucocyanin derivative [13].

Hypolipidemic activity
The aqueous extract of FB bark significantly showed a hypolipidemic effect in alloxan-induced diabetes mellitus in rabbits.Medication for one month at a dose of 50 mg/kg body weight/day reduced the levels of total cholesterol in serum from 82 ± 11 mg% and 118 ± 10.6 mg% to 42.7 ± 3.1 mg% and 51.7 ± 4.7 mg% in sub-diabetic and diabetic rabbits respectively.Low-Density Lipoprotein cholesterol and Very Low-Density Cholesterol values were found to reduce from 34 ± 10 mg% and 95 ± 24 mg% to 16 ± 3 mg% and 29 ± 4 mg respectively.Triacylglycerol (TAG) levels reduced from 121 ± 21.6 mg% and 416 ± 70 mg% to 45 ± 5 mg% and 81 ± 27.5 mg% respectively in sub-diabetic and diabetic rabbits [50].The aerial roots of the plant showed a significant hypolipidemic and hepato-protective effect in STZ-induced diabetic rats with a significant increase in HDL cholesterol level and a decline in the levels of Total Cholesterol (TC), Triglycerides (TG), LDL, and Very Low-Density Lipoprotein (VLDL) [15].Leucodelphinidin derivative (High Density Lipoprotein Cholesterol i.e.HDL-C) and quercetin derived from the bark showed a marked reduction in TC, LDL-C, atherogenic index, and an increase in the HDL-C levels in hyperlipidaemic rats by increasing faecal excretion of bile acids and cholesterol [51].

Hypotensive activity
In normotensive and angiotensin II-induced hypertension rats, an aqueous preparation of FB stem bark demonstrated considerable hypotensive action.Intravenous infusion of 10 mg/kg aqueous extract showed a decrease in systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MABP), and heart rate (HR) in normotensive rats compared to the control group by 10, 17, and 29 %, respectively while, in angiotensin II-induced hypertension group,   FB extract successfully decreased the SBP, DBP, and MABP by 27, 30, and 29 %, respectively without an apparent decrease in HR [11].

Anti-inflammatory activity
Evidence from various studies suggests the strong anti-inflammatory action of FB.The oral dosing of ethanolic extracts of young plant bark exhibited a remarkable reduction in inflammation in the carrageenaninduced rat paw oedema model and cotton pellet granuloma model compared to indomethacin in a dose-dependent manner [21].The aqueous extract of the stem bark showed a significant reduction in colon mucosa damage index, disease activity index, and myeloperoxidase in 2, 4,6-trinitrobenzenesulfonic acid (TNBS) induced inflammatory bowel disease in albino Wistar rats.The Malondialdehyde (MDA), Nitric oxide (NO) levels, and mast cell degranulation decreased significantly while the Superoxide dismutase (SOD) activity increased in the colon.Also, histopathological analysis of the colon of treated rats showed less progression of inflammatory bowel disease (IBD) and was characterized by a decrease in hyperplasia and oedema, a decline in the infiltration of the inflammatory cells, mild necrosis, and ulceration [51].The anti-inflammatory activity of the ethanolic extract of leaf was elicited in another study, with a significant reduction in paw volume (65.21%) at a dose of 200 mg/kg [17].
Moreover, the in-vitro anti-inflammatory property of different extracts of the bark was also evaluated by various researchers by estimating the human red blood cell membrane stabilization (HRBC) method and the results showed significant stabilization towards membrane at a concentration of 200 mg/ml in comparison to the standard drug, diclofenac sodium [16,52].Another study discovered that the fatty acid glycoside extracted from FB is a natural EGFR inhibitor, NO-releasing, and COX-inhibiting anti-inflammatory drug through suppression of the EGFR/Akt/PI3K pathway.It also reduced TNF-α, IL-6, and PGE2 expression [53].Another study showed that the oven-dried fruits of FB showed high levels of anti-inflammatory action through protein denaturation assay (44.79 ± 3.26% at 0.5 mg sample) [33].A gene expression study demonstrated strong anti-inflammatory activity of the hydroalcoholic extract of the bark by downregulation of TNF-α expression and upregulation of IL-10 expression through xanthine oxidase inhibition as shown in Fig. 5 [54].
Human xanthine oxidoreductase (XOR) performs major functions like purine catabolism that includes conversion of hypoxanthine to uric acid through xanthine dehydrogenase (XDH), production of ROS by xanthine oxidase (XO) activity and NADH oxidase activity and nitrite reductase activity that generates nitric oxide.XO delivers electrons directly to molecular oxygen (O 2 ), thus generating the reactive oxygen species (ROS) i.e., superoxide anion (O 2− ), and hydrogen peroxide (H 2 O 2 ).Further, hypoxia-mediated acidic pH and low O2 tension also increase the production of O 2− via decreased nitric oxide (NO) formation through NO synthase and increase its potential to uncouple.All free radicals thus formed including H 2 O 2 , O 2-and NO have an oxidizing effect, thereby contributing to oxidative stress.In a pathological state, the circulating XOR gets converted to oxidase form and binds to endothelial cells inducing proinflammatory response (TNF) and organ damage.The proinflammatory activity by XOR-derived ROS affects the microvascular lining and induces atheromatous plaque formation (adipogenesis).Also, studies show that ROS facilitates adipocyte differentiation by accelerating mitotic clonal expansion.The pathological adipocyte-derived factors disrupt vascular homeostasis and contribute to endothelial vasodilatory dysfunction leading and subsequent hypertension.The pro-inflammatory cytokine TNF stimulates the production of endothelin 1 and angiotensin which leads to vasoconstriction and hypertension.
Sabi et al. in their invitro study demonstrated that Ficus benghalensis hydro-alcoholic bark extract showed dose-dependent reduction in xanthine oxidase activity, ROS, NO levels, and pro-inflammatory cytokine (TNF) and upregulation of anti-inflammatory cytokine (IL10) thus exhibiting strong anti-inflammatory activity [54].Hence, this demonstrates the potential use of FB in inhibiting adipogenesis further endothelial dysfunction, and hypertension leading to following thromboembolic disorders.
Among various In-vitro studies, the plant showed important activities responsible in the management of thromboembolic disorder (Table 3).The aqueous extract of stem bark of FB showed significant inhibition of microsomal lipid peroxidation (LPO) in a concentration dependant manner with IC50 value 80.24 μg/ml [57].Methanolic extract of leaves showed strong anti-oxidant activity through a concentration-dependent increase in DPPH radical scavenging with an IC50 value 11.21 μl, a dose-dependent increase in total antioxidant activity, iron chelating activity as well as reducing power was also observed [34].
The in vitro antioxidant activity of methanolic extract of the latex also showed high DPPH scavenging activity along with IC50 value 28.63 ± 0.16 μg/ml, high ferric chloride scavenging with (IC50 49.82 ± 1.00 μg/ ml) and a significant decrease in the concentration of phosphomolybdenum radical due to scavenging potential IC50 value 31.84 ± 0.12 μg/ml [60,61].
In addition to this, collective information of FB extracts and its overall biological activities are represented in Fig. 6, while detailed invivo studies is mentioned in Table 4.

Toxicity studies
Plants may have compounds that have agonistic or antagonistic natures which can exhibit potential toxic effects, trigger hypersensitivity reactions, or sometimes lead to anaphylactic shock.As a result, it is critical to assess the unfavourable and toxic effects of isolated plant extracts and phytochemical substances intended for human treatment.Evidences from various studies highlight the safe dose and potential toxic effects of various parts of FB.

Aerial roots
The acute oral toxicity study of aqueous extract on healthy albino Wistar rats, showed normal rat behaviours and no mortality or toxic effects when orally administered with a single dose of 300 mg/kg aqueous extract 10 and 15 times [15].Methanolic extract of FB aerial roots using Swiss albino mice at doses ranging from 500 to 5000 mg/kg at various dose levels showed no mortality or any signs of behavioural changes up to 48 h of treatment [56].Similarly, another study showed that the ethyl acetate extracts of FB aerial roots in the dose of 5000 mg/kg body wt.did not induce any harmful effects on behaviour, neuro-motor abilities, body weight, water-feed intake pattern, liver and kidney functions or mortality in female Wistar rats throughout the 14-day trial in comparison to the corresponding control group.Thus, it can be inferred that the potential oral fatal dose of Ethyl Acetate Extracts of FB Aerial Roots is greater than 5000 mg/kg body wt.Which makes it safe for oral consumption [62].Another acute toxicity study carried out on the ethanol and aqueous extracts of aerial roots at a dose of 3000 mg/kg body weight showed no mortality or negative changes in behavioural, neurological and autonomic profiles in the rats after 24 h and 72 h [63].Successive methanolic extracts of aerial roots administered as a single bolus dose of 2000 mg/kg orally showed no mortality and physical/behavioural changes on rats when observed over 14 days [64].

Bark
In an acute toxicity study of oral administration of a partially purified preparation from the water extract of the bark showed LD 50 value − 1 mg/kg which was much higher and safer when compared to the control drug chlorpropamide (LD 50 760 mg/kg) [65].Results from another study elicited that oral administration of 5000 mg/kg aqueous extracts of bark in Swiss Albino male mice showed neither treatment related signs of acute toxicity nor mortality during the course of 14 days treatment.Also, the same were observed in sub chronic 28 days oral toxicity study at high dose of 1000 mg/kg/wt [66].In another study, ethanolic and aqueous extracts of the bark showed no signs of toxicity or mortality at 2000 mg/kg dose level at a total of 14 days [67].
High LD50 values and non-toxic effects were observed in male Wistar rats on a number of parameters including blood glucose, serum cholesterol, liver and kidney function tests, haemoglobin, total and differential leukocytes, and histopathological parameters of the liver, heart, and kidneys at high doses (50, 100, and 150 mg/kg) during the course of three months of chronic toxicity studies [65].

Fruit
Methanolic extract of FB fruit was studied for acute toxicity at dose of 2000 mg/kg i.p. in female albino mice.The extract did not cause any mortality even at repeated dosing using 3 new mice.Hence, 5000 mg/kg was taken as Lethal Dose (LD50) cut-off value as per fixed dose method of OECD guideline number 423 [68].

Seeds
Following a 14-day period, oral administration of a single dosage (2000 mg/kg body weight) of seed extracts to male and female Wistar albino rats did not result in any atypical clinical symptoms or behavioural patterns or evidence of acute toxicity [69].

Whole plant
On 14 days of therapy, the methanolic extract of the whole plant, given orally to female mice at dosages of 2000 and 5000 mg/kg bd.wt., exhibited no evidence of toxicity, confirming its safety against acute toxicity models [70].
Hence, to the best of our knowledge no such studies have been reported so far that highlights the potential toxic effects of FB extracts which makes it practically safe, non-toxic and well tolerated for long term use in managing thromboembolic disorders.

Conclusion and future perspective
FB has garnered much attention in the past as well as in the present due to its variety of medicinal uses owing to an array of biochemical constituents present in it.Findings from several experimental studies have indicated that FB may be effective against various thromboembolic disorders (Tables 3 and 4).Since thromboembolic diseases are multifactorial, the pleiotropic and multimode actions of FB have been indicated to prevent oxidative stress, inflammation, atherosclerosis, thrombosis, dyslipidaemia, and hypertension, proposing its effect.Although FB's antioxidant activity could be the primary reason for its protective effects, research suggests that phenolic compounds, that comprise a phenolic ring with one or more hydroxyl groups, are mainly accountable for scavenging free radicals, preventing lipid peroxidation, chelating metal ions, reducing atherogenic index and correcting dyslipidaemia.Moreover, the hydroxyl groups may control the generation ROS, inflammatory cytokines, blood pressure reduction, platelet activation, and damage to vascular endothelial cells.The data from current studies demonstrate the potential role of FB in cardiovascular health pertaining to thromboembolic disorders.However, further analyses should be carried out to assess the unexplored cardiac activities such as cardiotonic effects, diuretic/decongestive effects, anti-ischemic effects on endothelial functions, anti-ischemia-reperfusion injury, and antihypertrophy to measure the compound's perspective and rational use of the desired phytoconstituents.Since, it is not yet introduced for use as a medicinal agent, clinical trials should be done to confirm the safety and efficacy in patients with thromboembolic disease.
Besides that, the accuracy, reproducibility, and commercial viability of bioactive compound isolated from FB should be confirmed.In conclusion, the present review provides potential information on the studies that have already been carried out and close any research gaps for pharmacological aspects that might need value addition through some experimental studies to the data related to this species.

Sources of funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Fig. 4 .
Fig. 4. Pharmacological activities of FB in the management of thromboembolic disorders.

Table 3
Overview of in vitro studies related to FB in the management of thromboembolic disease.

Table 4
Overview of in vivo studies related to FB in management of thromboembolic disease.