Short communication

Diuretic and urolithiatic activities of the aqueous extract of the fruit of Randia echinocarpa on rats

Randia aculeata (Rubiaceae) is a medicinal plant distributed in the state of Jalisco, Mexico. In folk medicine it is used to counteract the effects produced by the bite of snakes and other poisonous insects. However, there are no reports of new alternatives to use the plant in a sustainable way. The main objective of this study was to establish a cell culture of R. aculeata, evaluate its anti-inflammatory and antibacterial potential and determine the phytochemical profile. In addition, we determine the total phenolics content and antioxidant activity of methanol extracts. Cell suspension cultures (CSC) was established with 2.0 mg/L 1-naphthaleneacetic acid and 0.5 mg/L 6-furfurylaminopurine in MS culture medium. CSC produced 13.77 ± 0.49 g/L biomass in dry weight at 36 days of culture. GC-MS analysis showed high amounts of β-sitosterol for hexane (HE-L: 22.02 ± 0.44%) and dichloromethane (DE-L: 19.69 ± 0.49%) leaf extracts. Hexane CSC extract (HE-CSC) stood out for containing high amount of palmitic acid (43.95 ± 0.02%) and dichloromethane extract (DE-CSC) had mainly palmitic acid (30.16 ± 2.14%) and vanillic acid (10.23 ± 0.34%). The methanol CSC extract (ME-CSC) showed antioxidant activity with an IC₅₀ value of 16.49 ± 0.25 µg/mL, which was almost equal to the methanol leaf extract (ME-L) that showed a IC₅₀ of 14.37 ± 0.20 µg/mL. The HE-CSC and DE-CSC were the only ones that showed inhibition against S. aureus, S. aureus-MRSA, S. typhimurium and E. coli. However, S. aureus was the most susceptible with HE-CSC (MIC = 62.5 µg/mL) and DE-CSC (MIC = 125 µg/mL). The HE-CSC exhibited the highest percentages of inhibition of NO production (36.88 ± 4.35%) at 40 µg/mL in RAW 264.7 macrophages, which was slightly lower than indomethacin (47.45 ± 7.41%) tested at 30 µg/mL. This extract was also the most effective against bacteria. The results suggest that cell culture extracts of R. aculeata may be a sustainable source for obtaining bioactive compounds.

Zanthoxylum heitzii is a medicinal plant widely used in central Africa for the treatment of many diseases, especially cardiovascular diseases and hypertension. The diuretic effects of crude stem bark extraction were determined and its safety in rats was evaluated.

The diuretic effects of crude stem bark extraction of Z. heitzii were investigated in Wistar rats (250 g ± 10 g) of both sexes. The crude stem bark extraction of Z. heitzii at the doses of 225, 300 and 375 mg/kg was administered to rats at 5 mL/kg body weight. Urine volume was determined 1, 2, 3, 4, 5, 6 and 24 h after administration of the extract. Kinetics of electrolyte elimination in response to a single oral administration dose of acute treatment was measured. The experiments were performed under the same conditions with two synthetic pharmacological diuretics considered as reference (furosemide and hydrochlorothiazide). Urinary and plasma concentrations of sodium and potassium ions were determined using flame photometry. Concentrations of creatinine, urea, glucose, albumin and electrolytes in the plasma and urine samples were evaluated using a two-way digital bidirectional spectrophotometer. The osmolarity of plasma and urine samples was measured by cytometry using an osmometer. Aldosterone was measured by radioimmunoassay.

The plant extract accelerated the elimination of overloaded fluid and increased urine volume and the excretion of Na⁺, K⁺ and Cl⁻ 24 h after administration (P<0.05). The increase in elimination of Na⁺, K⁺, and Cl⁻ induced by the extract caused alkalinization of the urine, and showed a strong inhibitory effect on carbonic anhydrase and saluretic. These effects were mainly observed at the dose of 375 mg/kg. At the maximum diuretic response, urinary osmolarity decreased significantly (P < 0.05) when compared to controls. The stability of aldosterone level, the absence of correlation with the plasma levels of Na+, and increased clearance of free water in the animals treated with extract indicated that increased diuresis and natriuresis were tubular in origin. No significant (P > 0.05) changes were observed in the body temperature of the animals.

The significant increase in urine volume 24 h after treatment followed a dose-response pattern. The excretion of Na⁺, K⁺ and Cl⁻ caused a decrease in urine osmolarity. The stability of aldosterone, the absence of correlation with the plasma levels of sodium, and increased clearance of free water in animals treated with aqueous extract suggest that increased diuresis and moderate natriuresis elevation were of tubular origin.

To assess the putative diuretic and antioxidant properties of Cassia occidentalis (C. occidentalis) leaves' aqueous extract.

Adult rats were administered with C. occidentalis leaves aqueous extract acutely (24 h) and subchronically (7 d), at doses 80, 160, 240, 320, and 400 mg/kg (per os). Negative control group received only an equivalent volume of distilled water, while the two positive control groups received the diuretic drugs furosemide (20 mg/kg, ip.) and hydrochlorothiazide (HCTZ) (20 mg/kg, ip.). Urinary elimination of electrolytes in response to treatments was evaluated, together with changes in concentrations of creatinine, urea, aldosterone, glucose, and albumin in urine and plasma. Various urinary indicators of kidney function and plasmatic markers of oxidative stress were also assessed.

The acute administration of C. occidentalis increased the urinary excretion of 107.58% at the higher dose tested, compared to negative control. The reference drugs furosemide and HCTZ induced increases of 84.27% and 48.05%, respectively. Acutely, the extract induced Na⁺ and Cl⁻ elimination, whereas subchronically an increase in K⁺ elimination was also observed. The extract also improved the kidney function indexes and oxidative stress markers. These effects were dose-dependent and comparable with positive control observations.

Our findings strongly suggest that C. occidentalis aqueous extract has diuretic and antioxidant activities, and deserves further studies considering the potential for the treatment of hypertension.

Melanins have important pharmacological properties with limited applications due to their poor solubility. Soluble melanins have been reported in different organisms, but not in plants. In this study, aqueous soluble melanins, Impure (IMe) and Partially Purified (PMe), were prepared from the edible pulp of fruits native to Mexico (i.e. Vitex mollis, VM; Randia echinocarpa, RE; and Crescentia alata, CA). IMe and PMe were tested for their phenolics content (TPC), antioxidant activities (AA), α-glucosidase inhibition (αGI) and spectroscopic features (UV-Vis and IR). Melanins of VM showed the highest TPC (222.23 mg GAE/g) and AA (ABTS 2779.30 μmol TE/g; FRAP 1203.70 μmol TE/g). Purified melanins (PMe) showed better αGI than acarbose (IC₅₀ = 8.38 mg/mL). The spectroscopic features of IMe and PMe corresponded to melanins and solubility may be by their complexation with carbohydrates. For the first time, plant-based soluble melanins and their remarkably high antioxidant and α-glucosidase inhibitory characteristics are presented.

Randia echinocarpa is a native plant from Mexico that produces an edible fruit with several ethnopharmacological uses (e.g. cancer, kidney ailments, and diabetes). Extracts of this fruit have shown antimutagenic activity. In this report, a methanolic extract of R. echinocarpa and a bio-guided chromatographic strategy were used to obtain an hexanic fraction (HF) with strong antimutagenic activity (microsuspension assay with Salmonella typhimurium YG1024) using 1-nitropyrene as mutagen (1-NP, 50 and 100 ng/tube). The HF (500 ng/tube) showed the highest inhibition percentage of mutagenic activity (PI) (75%, 1-NP 50 ng/tube; 84%, 1-NP 100 ng/tube). HF chromatography with silica produced HF₁ which was further separated to produce the fractions with the highest antimutagenic activities (HF_1–1 and HF_1–2, PI ≥ 60%). These fractions were chemically characterized by chromatography and gas chromatography–mass spectrometry; among the main components of HF, HF_1–1 and HF_1–2 were registered linoleic acid, palmitic acid and β-sitosterol, which could be responsible for the antimutagenic activity of R. echinocarpa fruit. The samples evaluated were neither toxic nor mutagenic. Randia echinocarpa is an underutilized plant and its fruit has been used traditionally as food/medicine; fruit consumption could provide human health benefits and it has potential to be exploited under conditions of ecological sustainability.

Palicourea coriacea (Cham.) K Schum, is an endemic plant used in the Midwestern Region of Brazil, popularly known as “douradinha do campo” and “congonha do campo”. This plant has been used in traditional medicine for several ailments, especially to treat kidney diseases. Since no formal studies on the biological activities and medicinal properties of the ethanolic extract of Palicourea coriacea (PCEE) have been carried out previously, the present study represents the first research into the efficacy of this plant as a diuretic agent employing laboratory rats as test animals.

For diuretic activity evaluation we assayed three doses of PCEE (20, 40 and 80 mg/kg) and measurement of the urinary volume and electrolytes (Na⁺, K⁺) concentration were taken. The acute oral toxicity of PCEE was investigated according to OECD Guideline 423.

The oral administration of a single dose of PCEE significantly increased the urinary volume in 24 h. Additionally, the treatment with PCEE increased, in a dose-dependent manner, the excretion of both, Na⁺ and K⁺. No sign of toxicity was observed in the animals.

The present study confirmed the ethnopharmacological use of Palicourea coriacea as a diuretic agent in the experimental condition tested here. Additionally, this work supports the importance of the preservation of local knowledge as well as the conservation of Brazilian biodiversity.