Genetic diversity in nutritional composition of oat (Avena sativa L.) germplasm reported from Pakistan

Graphical abstract


a b s t r a c t
In the present study, 30 potential germplasm of oat (Avena sativa L.) were subjected to proximate, elemental, and HPLC analysis to provide a scientific basis to genetic diversity present among them. The extracts of the selected germplasms were also evaluated for their antioxidant potentials through DPPH and ABTS assays. Proximate analysis showed protein contents to be in the range 8.35-17.72% with the highest protein contents in the accession line 22,365 (17.72 ± 0.38%). The genotype-725 showed the highest carbohydrate, and dry matter (53.35 ± 0.01 and 93.50 ± 0.07% respectively) contents whereas, the germplasm-830 contained the highest fat (7.88 ± 0.12%) contents while the highest moisture contents were there in germplasm-22348 (11.95 ± 0.06%). The crude fiber contents (19.67 ± 0.19%) were found high in germplasm-832. The mentioned contents were also correlated to each other where a negative (À0.431*) correlation was noted for crude protein and carbohydrate while ash content to crude protein has a positive (0.38*) correlation. A positive and a negative correlation were there in Crude fats/crude protein (0.30*) and crude fats/moisture contents (À0.39*) respectively. Principal component analysis showed an Eigenvalue of 0.76 with a total variation of 85.01% when applied to proximate components. Based on cluster analysis to proximate composition all the oat germplasms were divided into 5 subclusters, where accession numbers 769 and 817 were found to be the most diverse genotypes. The elemental analysis confirmed the presence of magnesium (2.89-7.62 mg/L), sodium (3.71-8.03 mg/L), manganese (0.93-3.71 mg/L), copper (0.35-3.36 mg/L), iron (2.15-6.82 mg/L), zinc (1.30-3.37 mg/L), chromium (0.37-3.34 mg/L), and potassium (50.70-59.60 mg/L) in the selected germplasms. Principal component analysis for elemental composition showed the total variation of 73.75% with the Eigenvalue of 0.97. Cluster analysis on an elemental basis divided all the oat germplasms into 7 subclusters where accession numbers 769 and 22,350 were found to be the most diverse germplasm. Phytochemical analysis performed through HPLC resulted in the identification of nine possible compounds (malic acid, epigallocatechin gallate, quercetin, morin, ellagic acid, catechin hydrate, rutin, pyrogallol, and mandelic acid) in various germplasm of oat. A concentration-dependent antioxidant response was recorded when extracts were tested as an inhibitor of DPPH and ABTS free radicals. The results revealed that oat grains are a good source of nutrients, minerals, and phytochemicals that can be used

Introduction
Cereals are cultivated for their nutrient-rich edible grains and are used as food everywhere around the globe. Since the beginning of civilization, certain cereals, such as oat and barley have been used by humans as a staple food, directly or indirectly in terms of livestock feed (Barcchiya et al., 2017). Oats (Avena sativa L) are grown all over the world. After wheat, corn, rice, barley, and sorghum, oats are the only grain that is unique among all grain types with rank as sixth in world grain production (Ahmad et al., 2014).
It has been proved experimentally that the phytochemical, elemental, and primary metabolite compositions among different cultivars of the same species are different. To fulfill the human nutrition and health requirements one should select better varieties. Genetic diversity among different cultivars is determined in several ways (Ibrahim et al., 2020). However, in selecting better germplasms with high nutritional values, the determination of diversity for proximate and elemental compositions is a better option. Oats have long been used as a nutritious food. It is a tasty and nutritive food that provides carbohydrates in the form of starch, well-balanced proteins, high lipid levels (Ibrahim et al., 2020). In addition, oatmeal contains small amounts of B vitamins, specifically thiamine, folate, biotin, and pantothenic acid (Gu et al., 2021). Its protein can maintain a good balance of essential amino acids in the body when eaten as food. Many basic amino acids are found in oats, including methionine, cysteine, threonine, isoleucine, tryptophan, valine, leucine, histidine, methionine, phenylalanine, and tyrosine (Biel et al., 2020). Oat crops are commonly used as a companion crop for forage legumes under seedlings. Grains like wheat, maize, barley, and rice provide less protein, fatty acids, iron, magnesium, phosphorus, and zinc in comparison to oat (Gu et al., 2021). In addition, oat is a rich source of fibers (especially b-glucan) and minerals (manganese, phosphorus, copper, iron, selenium, magnesium, and zinc). The bioactive compound present in oats such as phenolics, carotenoids, and sterols is essential for the maintenance of good human health (Ibrahim et al., 2020). It has been reported that oat products in gluten-free and normal diets have a significant role in controlling coeliac disease in humans (Smulders et al., 2018).
The popularity and consumption of oats have increased significantly, however, its output has steadily declined for a few years, especially in Europe (Stewart and McDougall, 2014). Today the food industry is investing significant efforts in increasing the use of oats as an ingredient in the formulation of new food products. The development of new oat products can add more functional foods to the market and would prevent chronic diseases (Ję drusek-Goliń ska et al., 2020). In Pakistan, oat is primarily grown as a forage crop on 3.52 million hectares, yielding 264 tons per year. The Punjab province contributes 2.03 million hectares, with oats accounting for more than 35% of the total production (GOP 2014). Oat can tolerate acidic soils better than other small grain cereals showing that the plant has the potential to be grown in varied environments (Chen et al., 2021).
To revive the importance of this plant there is an urgent need to evaluate proximate and elemental composition differences among different cultivars to select the better variety that would have unique health benefits. Therefore, the present study is aimed to figure out proximate and elemental composition differences among high-yielding (30 accessions) oat germplasm out of 236 breeding lines. The most favorable varieties were also subjected to HPLC analysis whereas the antioxidant potentials determined through DPPH and ABTS assays were also evaluated.

Plant material
During 2018-2019, 236 genotypes were evaluated for agro morphological and biochemical characterizations in Botanical Garden University of Malakand, Khyber Pakhtunkhwa, Pakistan. The seeds were obtained from Plant Genetic Resources Institute (PGRI) National Agriculture Research Centre Islamabad, Pakistan. About 30 potential high-yielding genotypes were subjected to proximate and elemental composition analysis to get the most potent variety (Table 1).

Proximate analysis of Avena sativa L. germplasm
About 100 g oat seed samples were finely grounded and subjected to proximate analysis (Horwitz, 2010). In a pre-weighed petri-dish, 3 g of oat powder was weighed and then dried for 6-12 h at 100°C to determine moisture contents. The dish containing the sample was weighed after cooling in desiccators and differences between the weight before and after moisture contents were estimated.
To determine ash contents, 1 g flour was taken in a crucible which was then placed in a muffle furnace at 550°C for 5 h. After cooling the crucible weighed. By subtracting crucible weight ash contents were estimated.
To estimate protein contents, the sample (1 g) was digested with concentrated H 2 SO 4 in the presence of CuSO 4 and Na 2 SO 4 and heated. The ammonia produced was steam distilled into a boric acid solution. The ammonia nitrogen was estimated through titration of the trapped ammonia with 0.1 M HCl (double indicator) in presence of Tashirus indicator until the purple-pink color was observed. The deduced nitrogen value was multiplied with a factor of 6.25 mg to get crude protein weight.
For fat contents estimation, 1 g sample of each was extracted with ether (10 mL). Every time tubes were placed for 12 h at 40°C in the incubator. The upper layer from solutions was transferred to graduated tubes which were then dried in the oven for 4 h at 40°C to ensure complete evaporation of ether. The weight differences in the tube contents before and after evaporation were considered as fat contents.
About 2 g of powder digested in 50 mL of 1.25% H 2 SO 4 and boil for 30 min. The filtrates were then digested with 50 mL of 1.25% NaOH and heated for 30 min and filtered. The filtrates were then dried in the oven and finally heated to 550°C in a furnace. The weight of the residue left after the ignition was used to calculate the fiber content, which was expressed in terms of the weight of the sample before ignition. Carbohydrate (CHO %) contents were then estimated from the relation: CHO% ¼ ½100 À moisture% À protein% À fat% À ash% ð 1Þ

Atomic Absorption spectrometry
The fine powder of oat seeds was used for the elemental analysis through Atomic Absorption Spectrophotometer (Shimadzu AA-670) following standard methods (Association of Official Analytical Chemists (AOAC) to investigate the mineral composition of oat germplasm (Horwitz, 2010). About 0.25 g of plant material was put in a 50 mL flask containing 6.5 mL mixed acids solution; Nitric acid (HNO 3 ), Sulfuric acid (H 2 SO 4 ), and Perchloric acid (HClO 4 ) in 5:1:0.5 ratios. The samples were boiled on a hot plate in a fume hood (model VWR VELP scientifical, Germany). After that, a few drops of distilled water were added to finish the digestion, which resulted in white fumes coming out of the flask. After cooling the digested samples were then moved into a 50 mL volumetric flask. The volume of the mixture was made 50 mL with distilled water. The samples were then filtered using filter paper; Whatman No. 42 and were stored till further use. The corresponding standard calibration curves were used to calculate the percentage of selected metals.

Sample preparation for HPLC-UV
HPLC profiling was made for 15 samples using an Agilent 1260 system following a reported method (Zeb, 2015). About 1 g pow-dered sample of oat germplasm was digested with methanol and water (1:1; 20 mL; v/v). The mixture was heated at 70°C for 1 h in the water bath and centrifuged for 10 min at 4000 rpm. After that sample (2 mL) was filtered into HPLC vials through Whatman filter paper and labeled with proper codes. Identification of phenolic compounds was made through a comparison of sample retention time with that of available standards.

DPPH free radical scavenging
Antioxidant activity of the oat germplasm extract was determined using the Brand William assay (Brand-Williams et al., 1995). To prepare DPPH (2, 2-Diphenyl-1-picrylhydrazyl) solution about 2 mg DPPH was dissolved in 100 mL of methanol. The stock solutions of oat germplasm extract were prepared to have concentrations range 1 mg/mL in methanol and then diluted to the concentrations of 1000, 500, 250, 125, and 62.5 lg/mL. About 0.1 mL diluted solution of each plant part extract was mixed with 3 mL of DPPH solution in methanol and was incubated at 25°C for 30 min. Finally, the absorbance was measured at 517 nm. Ascorbic acid was used as a positive control. Each concentration was taken in triplicate and the data obtained were presented as mean ± S.E.M. The percent free radical scavenging activity was calculated using the following equation: Percent scavenging activity ¼ Contol Abs À sample Abs control Abs Â 100 ð2Þ 2.7. ABTS free radical scavenging Antioxidant potentials of the oat germplasm extracts were also assessed using the free radicals of ABTS (2, 2-azino bis [3-ethylbenz thiazoline]-6-sulfonic acid) following standard procedure (Re et al., 1999). The stock solution (1 mg/mL) of oat germplasm extract samples were prepared in methanol and then diluted to the concentration range of 1000, 500, 250, 125, and 62.5 lg/mL. Solutions of ABTS (7 mM) and potassium persulfate (2.45 mM) were prepared and mixed thoroughly. For free radicals' formation, the solution was kept overnight in the dark. After incubation, the absorbance of ABTS solution was adjusted to 0.7 at 745 nm by the addition of methanol (50%). Then 300 lL of test samples were mixed with 3 mL of ABTS solution and then absorbance was measured using a double beam spectrophotometer for 6 min. For positive control ascorbic acid was used. The results were recorded in triplicate and percent ABTS free radicals scavenging activity was calculated using equation (2).

Statistical analysis
All experiments on each oat tested line (germplasm) were performed in three replicates. MS Excel 2016 was used to estimate the mean, cumulative variability (C.V) percent, standard deviation, and other statistics. The mean data of all the studied parameters were subjected to cluster analysis to visualize the cluster dendrogram using linkage analysis, principal component analysis using PC ORD version 5.0, and Statistica version 7. Pearson correlation coefficients were estimated using SPSS version 22.
For antioxidant studies, One-way analysis of variance (ANOVA) followed by Dunnett's posthoc multiple comparison test was used to determine the values of P. P < 0.05 were considered as significant. All the assays were repeated in triplicate and values have been expressed as Mean ± SEM. Linear regression was used to calculate the IC50 values from % inhibition of DPPH and ABTS of different concentrations of oat tested line (germplasm) samples using Excel 2007. (IC50 = half-maximal inhibitory concentration is a measure of the potency of a substance/plant extract in inhibiting free radicals of DPPH and ABTS).

Proximate contents
In the current study dry matter ranges from 87.60 to 93.50 with the mean value of 90.76, and C.V = 1.71. Minimum dry matter (87. 6 ± 0.05) was found in accession number 830, while maximum (93. 50 ± 0.07) in accession number-725 (Table 2). A significant variation was also found in crude protein contents ranged from 8.35% to 17.72% (mean value = 14.54%; C. V = 15). Minimum crude protein (8.34 ± 0.03) was found in accession number 726, while maximum (17.72 ± 0.38) in accession À22365. Ash contents were ranged from 3.88 to 8.89 with the mean value of 5.86 and C. V = 24.25. Minimum ash content (3.88 ± 0.01) was there in accession number 22349, while maximum (8.89 ± 0.02) was in accession number 721. Moisture contents were in the range; 7.81-11.95 with the mean value of 6.31 and C.V 11.9. Minimum moisture content was (7.81 ± 0.12) was recorded for accession number 839 while maximum (11.95 ± 0.06) for accession number 22348. Crude fats contents exhibited a significant variation ranging from 4.99 to 7.88 with a mean value of 6.31 and C.V of 13.13. Accession number 811 has shown a minimum quantity of fats (4.99 ± 0.11), while a maximum (7.88 ± 0.12) was found in accession number 830. The crude fibers variations were in the range from 10.27 to 19.67, with a mean value of 15.47, while C.V equal to 16.3. Accession number 22,389 exhibited minimum crude fiber contents (10.27 ± 0.02), while maximum (19.67 ± 0.19) by accession number 832 (Table 2). A significant variation in carbohydrate contents was also observed ranging from 37.52 to 53.40 with the mean value of 47.92 and C.V value of 7.05 with a maximum amount (53.35 ± 0.01) in accession number-725, and minimum (37.51 ± 0.05) in accession number-721.
The total variation for the 2nd PC was 54.75% and related positively with carbohydrate (0.56), dry matter (0.23), a protein (0.26) contents while the association of moisture (À0.34), ash (À0.33) and fibers content (À0.58) were negative. In PC3 the total variation was 71.02% and the association of dry matter (0.35), fats (0.47), and fibers (0.57) were recorded positive whereas crude protein (À0.11), ash content (À0.42), and moisture content (À0.38) were found negative. Furthermore, in PC4 the total variation was 85.01%, Eigenvalue was 0.76, and positive scores by weight were exhibited by carbohydrate (0.15) and fats (0.34), while dry matter (À0.88), crude protein (À0.12), ash (À0.11), and moisture contents (À0.26) were found negative. Biplot analysis was used to determine the associations between the traits. As a result, the plot defined by the two PCS: 2 and 3 into 54.75 and 71.02% (Fig. 1) and were placed against each other to find the level of genetic diversity and geographical association among the genotypes. The separation based on PC2 and PC3 revealed that the genotypes were scattered in all the quarters, which showed the highest level of genetic diversity in the studied genotypes, where the accession À817 and 721 have been placed at the left side of the quadrate while 725 and 839 at the right side of the quadrate. The genotypes-672, 723, and 843 have been presented with protein while accession 22,350 with dry matter whereas genotypes-22349 have been marked with fats.

Distribution of minerals elemental composition
The distribution of minerals and elements in 30 oat germplasm are presented in Table 4. Significant variations were observed for the selected elements among the germplasms. Mg ranged from 2.89 to 7.63 mg/L with a mean value of 5.47 and C.V of 23.25%. Maximum Mg (7.62 ± 0.15) was found in accession 830, while minimum (2.88 ± 0.10) in accession 22339. Na ranged from 3.71 to 8.03 mg/L with the mean value of 6.07 and C.V of 20.61%. The maximum quantity of Na (8.03 ± 0.56) was found in accession-22350, while minimum (3.711 ± 0.36) in accession-22365. Mn exhibited values from 0.93 to 3.71 mg/L with a mean value of 1.96 and C.V of 34.64%. Maximum Mn (3.70 ± 0.17) was found in accession number 22390, while minimum (0.92 ± 0.05) in accession-769. K was in the range of 50.70 to 59.60 mg/L, with the mean value of 54.26 and C.V% as 3.69. Accession line 725 displayed a maximum value of K (59.60 ± 5.35), while minimum by 841 (50.7 ± 0.24). Cr was ranged from 0.37 to 3.34 mg/L, with 50.21% C.V and a mean of 1.61. The highest (3.34 ± 0.29) Cr was found in accession number 830, while the lowest (0.36 ± 0.08) was observed in accession line 22393. Zn was in the range of 1.30 to 3.37 mg/L, with a %C.V of 25.34 and a mean value of 2.21. Accession number 726 exhibited maximum Zn (3.37 ± 0.11), while accession number 22,339 displayed minimum (1.30 ± 0.13) Zn contents. Cu exhibited variation from 0.35 to 3.36 mg/L with mean value and %C.V of 1.89 and 45.11, respectively. Maximum Cu (3.35 ± 0.18) was found in accession-723, while minimum (0.35 ± 0.14) in accession 769. Variations in Fe concentrations were from 2.15 to 6.82 mg/L with the mean value of 4.59 and CV% of 31.72%. Maximum Fe (6.81 ± 0.06) was present in accession number 811 while minimum in accession 22,335 (2. 14 ± 0.03) as shown in Table 4.

PCA for elemental composition
Principle component (PC1, PC2, PC3, and PC4) analysis for the elements like magnesium, sodium, manganese, potassium, chromium, zinc, copper, and iron distribution in selected germplasms were performed where a total variation of 73.75% and Eigenvalue of 0. 97 (Table S3) Table S3).
3.9. Antioxidant activity 3.9.1. DPPH free radical inhibition DPPH scavenging activity of s oat germplasms Met. Ext is presented in Table 6. The DPPH scavenging potential of methanolic extracts of accession line 22,347 was highest with an IC 50 value of 20 mg/mL, followed by lines 22,348 and 843 with IC 50 of 30 and 32 mg/mL respectively as shown in Table 6. Ascorbic acid was used as the standard for which the IC 50 value was 15 mg/mL.

ABTS free radical screening
ABTS scavenging activity of oat germplasms Met. Ext is presented in Table 6. Accession line 22,347 was found more potent with an IC 50 value of 25 mg/mL, followed by lines 22,348 and 843 with IC 50 of 32 and 35 mg/mL, respectively. For ascorbic acid, the IC 50 value was 18 mg/mL.

Discussion
Interest in oats has recently increased due to their nutritional value and health benefits. Macronutrients (fats, proteins, carbohydrates) provide energy and substances necessary for body growth, while micronutrients (vitamins and minerals) aid in the successful operation of metabolic pathways (Hans and Jana 2018). Secondary M. Ihsan, M. Nisar, N. Nazir et al. Saudi Journal of Biological Sciences 29 (2022) 1487-1500 metabolites are substances prepared by plants in an uneven situation to protect themselves from enemies or diseases. The knowledge of the nutritional and phytochemical constituents of a plant is particularly important for humans as they are directly or indirectly dependent on plants. In this connection, 30 oat germplasms were evaluated for nutritional (proximate), elemental, and phytochemical compositions.
Carbohydrates account for over 70% of the dry weight of cereals and are the most essential ingredient. A significant variation was found in carbohydrate contents with a minimum value in accession number-721, while the maximum was recorded for accession-725. At the same time, dry matter is ranged from 87.60% to 93.50% showing a connection with carbohydrate contents i.e. greater the carbohydrate contents greater will be the amount of dry matter. The finding shows that all varieties do not have the same amount of carbohydrates, being a primary metabolite. Thus accession-725 will be an excellent choice for breeders as oat flour could be a useful source of carbohydrates. Youssef et al., (2016) reported that the carbohydrates content of different oat genotypes can vary from 69.43 to 75.62%. According to Punia et al., (2020)  Oat is the potential source of proteins as it possesses high protein contents with a unique composition like; a high proportion of salt soluble globulins, which are endosperm storage proteins, whereas storage proteins in other cereals are insoluble in salt solutions (Mut et al., 2017). We observed a significant variation in protein content among the studied germplasms (8.35-17.72%), where maximum contents were recorded in accession-22365. Protein is an important indicator to measure the quality of oat grains. The protein content depends on environmental factors as well as genotypic factors. Prates and Yu (2017) recorded protein content in several oat germplasms which were from 148.7 to 216.6 mg/g. In another study, the contents recorded were from 30 to 280 mg/g (Bhardwaj et al., 2019), which is the highest value reported so far.
Appreciable variations in moisture (7.81-11.95%), ash (3.88-8.89%), and crude fiber contents (10.27-19.67%) were recorded as well. The present investigation is in agreement with that of the reported study of Youssef et al., 2016, where the authors have observed a significant variation in crude protein, moisture content, Table 4 Mean value, standard deviation, standard error, and coefficient of variation of magnesium, sodium, manganese, potassium, chromium, zinc, copper, and iron of 30 oat germplasms.  Usman et al., (2010) reported the ash content in oat genotypes which were ranged from 1.87 to 4.33%. Such variations are encountered as the developmental conditions, genetic factors, environmental factors, regional variations, and analytical approaches influence the results (Alam et al., 2020). Other factors like harvesting conditions, storage, and postharvest treatments can also lead to variations in the proximate components (Dhanalakshmi, 2021). In developing countries, grain, which is a good source of minerals, is used as a staple food. Minerals are necessary elements in human nutrition. The human body cannot produce minerals, so minerals must be supplied through food (Biel et al., 2020). A considerable variation was observed among the germplasms for the studied elements; magnesium (2.89-7.62 mg/L), sodium (3.71-8.03 mg/L), and manganese (0.93-3.71 mg/L). The minerals are important for proper growth of animal and human which plants concentrates in their tissues through phytoremediation. Mut et al., (2017) reported oat genotypes to contain 4.99%, 3.66%, and 1.50% of K, P, and Mg contents, respectively. According to Kose et al., (2021) K, P, and Mg contents in oats are in ranges 2.78-6.73 gkg À1 , 3.44-5.47 gkg À1 , and 1.16-1.90 gkg À1 . Ciolek et al., (2007) and Gambuś et al., (2011) have also observed significant variations in oat germplasms for K, P, Mg Ca, Mn, and Cu. The variations for other studied metals were as: Zn; 1.30-3.37 mg/L, copper; 0.35-3.36 mg/L, and iron; 2.15-6.82 mg/L. The study of De-Oliveira et al., (2021) showed Zn concentration was from 27.3 and 57.7 mgkg À1 , Fe from 38 to 63 mgkg À1 , Mn from 59 to 105 mgkg À1 , Cu from 4.1 to 7.6 mgkg À1 in the grain of white oat genotypes. The Zn accumulation found in this study is similar to that of other grains like wheat, maize, and rice (Velu et al., 2019). The zinc concentration in the rye (16-24 mg kg À1 ) and barley (6-33 mg kg À1 ).
To correlate the compositional variations in plants Principal Component Analysis is used. The PC1, PC2, PC3, and PC4 depicted the total variation to be 85.01% while in the case of elemental anal-ysis the total variation was 73.75%. Accession 769 and 817 were found to be the most diverse germplasm as depicted by nutritional component PCA while based on elemental analysis the accession 769 and 22,350 were the most diverse lines. Our results are in line with the reported study of Bhardwaj et al., (2019) where the authors have studied 43 oat germplasms. Kose, Mut, & Akay, (2021) screened 347 oat genotypes in the year 2012-2014 where PCA outcome indicated that 84% of the total variability among the genotypes.
Correlation analysis is important among the different nutritional contents as for a cereal it is important to have a proportionate composition. Negative and positive correlations were observed among different components as per giver details: crude protein and carbohydrate, negative; ash content with carbohydrate, and crude protein, positive; moisture content and crude protein, positive; crude fibers with crude protein and ash content, also positive. The recorded observations were in line with the reported study literature (Bhardwaj et al., 2019).
Consumption of oat has been associated with various health benefits that may be attributed to their nutritional value and phytochemical composition. Phytochemicals are the secondary metabolites that act as part of the defense system against diseases in plants. A total of nine phenolic compounds as given in the result section viz; malic acid, epigallocatechin gallate, quercetin, morin, ellagic acid, catechin hydrate, rutin, pyrogallol, mandelic acid have been identified in various oat germplasm. The compounds mentioned are associated with several health advantages if consumed by humans as reported by Nazir et al., (2018Nazir et al., ( , 2020. Most of these compounds are antioxidants, thus the use of oats would have substantial health benefits if consumed as cereal by humans. Although the present consumption of oats is lower than other cereals across the globe, it is getting popular in scientific and common communities due to its potential health benefits. As a source of antioxidants, it has been reported by other researchers as well and according to their findings, various phenolic compounds (phenolic acids, flavonoids, stilbenes, coumarins, and tannins) and phytic acid (Gangopadhyay et al., 2015) are responsible for the mentioned bio-    Table 6 Percent DPPH and ABTS free radical scavenging activity of Me. Ext of oat germplasm at various concentrations.

S. No
Oat Germplasm Concentration (mg/ml) %DPPH scavenging IC 50 (mg/ml) %ABTS scavenging IC 50 (mg/ml) Mean ± SEM Mean ± SEM logical potential. In addition to their dietary importance, oat antioxidants may also contribute to the stability and the taste of food products by donating their hydrogen to free radicals and prevent autoxidation (Redaelli et al., 2016).
The storage protein in oats has been found to have the presence of bioactive peptides which may play an important role in the prevention and control of various chronic diseases such as diabetes, cancer, and age-related issues, along with the advantage of having fewer side effects compared to the synthetic counterparts (Guo et al., 2014). Oats b-glucan lower glycemic index and postprandial glucose levels (Gupta and Mishra 2021). Avenanthramides are another class of polyphenols that have been reported from oat which act as an antioxidant by inhibiting low-density lipoprotein oxidation with the aid of Vitamin C (Pellegrini et al., 2016). It has also shown numerous other beneficial health-promoting properties such as antiproliferative, antiitch, anti-inflammatory, anticancer, and antiatherogenic effects and thus may be useful in the prevention of skin irritation, colon cancer, and coronary heart diseases. Bioactive compounds like coumarins, saponins, flavonoids, flavones, proteins, tocols, bglucan, and carbohydrates have also been reported from this plant by Singh et al. (2019).

Conclusions
Cereals are grown for their nutritionally edible grains and are consumed all over the world. Oats are the world's sixth most important grain crop, following wheat, corn, rice, barley, and sorghum. Oats have the potential to be a competitor in the category of super-food because they offer a wide range of healthpromoting characteristics and nutritional benefits. It contains all principle nutritional components like carbohydrates, protein, vitamins, minerals, antioxidants, and soluble fiber. Between 2018 and 2019, 236 oat genotypes were tested for agro morphological and biochemical characterizations at the Botanical Garden University of Malakand, Khyber Pakhtunkhwa, Pakistan. 30 potential highyielding seeds were subjected to proximate and elemental composition analyses to discover the most effective variant. The present study has not only confirmed the presence of these ingredients but also has depicted variation in their quantities among different germplasms which would enable the breeder to select the best varieties for future cultivars. Because of their nutritional value and health benefits, oats have become increasingly popular. The accessions; 725,22365,22348,830,22350,841, and 832 were found to have high nutritional components like carbohydrate, proteins, ash content, fats, and fibers. However, further confirmatory studies are needed to confirm the observed parameters in other localities too as the plant production, minerals, and phytochemical compositions vary with locality and particularly with the type of soil.

Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.