Comparative Phytochemical Composition and Hypoglycemic Activity of Some Plants Used by Traditional Healers to Treat Diabetes in Kisangani

Background: Phytochemical and Biological studies are always needed to define chemical composition, bioactivity and toxicity of plants from folk medicines before integrating them into conventional medicines. Here we compared phytochemical composition and antihyperglycemic activity of some plants used in Kisangani to treat diabetes.
Methods: The plants tested are Aloe vera (AV), Bidens pilosa (BP), Cassia alata (CA), Cassia occidentalis (CO), Catharanthus roseus pink flower (CRp), Catharanthus roseus white flower or alba (CRw), Mangifera indica (MI), Morinda lucida (ML), Morinda morindoides (MM), Panda oleosa (PO), Terminalia catappa (TC), and Vernonia amygdalina (VA). Their content in polyphenols, saponins, alkaloids and mineral ash were compared. Hyperglycemia was induced in rabbits by oral glucose tolerance test with glibenclamide 0.2 mg/kg as reference. Blood glucose level was assayed by Folin-Wu photometric method. The mean percentage in glucose level reduction (MPR) was calculated from control untreated animals. The relative potency of each extract (RP) was calculated from glibenclamide MPR taken as 100%.
Results: Flavonoids, tannins and saponins, were the main components; alkaloids were found only in CRp, CRw, ML and MM. The water content varied from 67% to 88%; Total ashes content was lower in roots (9%) than other parts (11-16%). Glibenclamide gave MPR=56.8% and RP=100%. MPR and RP for plant extracts were, ML(29.8%; 52.4%), CA(31.9%; 56.2%), MI(46.6%; 81.9%), MM(46.6%; 81.9%), TC(47.2%; 83.1%), VA(49.4%; 86.9%), CO(54.4%; 95.8%), CRw(57.4%; 101.0%), BP(60.8%; 107.0%), CRp(63.2%; 111.1%), AV(64.5%; 113.4%), PO(83.2%;146.3%). Conclusion: All plants but Panda oleosa have been studied by others; the main phytochemical groups reported have been confirmed in the local species. All plants exhibited some antihyperglycemic activity, differing however by their relative potency.