CHEMICAL CONSTITUENTS AND MEDICINAL APPLICATIONS OF SELECTED PLANT SEEDS AS POTENTIAL THERAPY FOR DIABETES MELLITUS

Abstract

The use of synthetic drugs for management of diseases such as diabetes is associated with medical challenges such astoxicity, cost and availability. Previous studies have reported the use of stems, leaves and barks of plants as recipes for managing diabetes. Due to underutilisation of selected plant seeds in the recipes for the management of diabetes mellitus, there is need for further investigations. Therefore, the aim of this study was to evaluate the chemical constituents and medicinal applications of some locally sourced plant seeds.

Seeds of Erythrococc aanomala (EA), Cyperus esculentus (CE), Butyrospermum paradoxum (BP), Blighia sapida (BS), Crotonpenduliflous (CP), Parkia biglobosa (PB), Momordic acharantia (MC), Monodora myristica (MM), Monodora tenuifolia (MT) and Picralima nitida (PN) were purposively collected and identified at the Herbarium Unit of Botany Department, University of Ibadan. The seeds were cleaned, air-dried, pulverised, digested and analysed for constituents elements by atomic absorption spectrophotometry. Extraction was carried out with methanol and concentrated on rotary evaporator. Qualitative and quantitative phytochemical and antioxidant constituents were determined following standard procedures.Fatty acid and bioactive contents of the extracts were analysed by Gas chromatography flame-ionization detector and Gas chromatography/Mass spectrophotometer, respectively. In vitro anti-diabetic assay was conducted on all the extracts using Bio-Tek ELIZA reader and Omega Flurostar ®. The most potent extracts were further subjected to in vivo test in wistar rats with alloxan-induced type 2 diabetes. Data was analysed using ANOVA at α0.05.

The concentrations in mg/kg of the predominant elements in the seeds of the plants were Mg, 99.13±0.17 (EA); Ca, 108.35±9.27 (BP); Fe, 83.47±6.80 (CE); K, 99.18±1.20 (CP); Ca, 86.79±1.97 (MT); K, 87.95±1.40 (BS); K, 52.94±1.47 (MM); Ca, 86.79±1.97 (MT); K, 98.98±1.05 (PN) and K, 83.99±0.06 (PB). Flavonoids, saponins, terpenoids, phenol, carbohydrates and sterols were detected in all the extracts. The phenols content ranged from 48.27±1.95 to 146±61 mgGAE/g, while flavonoids was 6.29±0.26 to 29.54±0.40 mgQE/g. PN displayed highest antioxidant activity against DPPH and FRAP with IC50 (µg/mL) of 12.20±0.75 and 1.04±0.03, respectively. Non essential fatty acids such as palmitic (1.16% to 13.46%), palmitoleic (0.27% to 6.26%), stearic (0.57% to 11.34%), arachidic (0.27% to11.06%), and oleic (2.50% to 30.70%) were confirmed in all the plant seeds. Similarly, essential fatty acids were linoleic (2.18% to 42.72%) and linolenic (0.38% to 6.40%). Octadec-9-enoic acid (54.80%, BP); 9, 12-Octadecadienoic acid methyl ester (53.68%, CE); Hexadecanoic acid methyl ester (7.82%, CP); Cyclohexene, 1-methyl-4-(5-methyl-1-methylene-4-hexenyl (17.99%, EA); Octadecanoic acid methyl ester (22.68%, MC); α-Cubebene (4.93%, MT); 8, 11-Octadecadienoic methyl ester (28.41%, BS); Octadecanoic acid methyl ester (34.86%,MM); Octadec-9-enoic acid (65.14%,PB) and Oleyl alcohol (23.96%,PN) were identified. In vitro screening revealed that all the extracts have antidiabetic activities, while in vivo test showed that BS, MM, PB and PN significantly lowered the fasting blood glucose.

The seeds of Blighia sapida, Monodora myristica, Parkia biglobosa and Picralima nitida have antioxidant, essential elements, fatty acids and phytochemicals which might be useful for the development of appropriate drugs for diabetes management.