Abstract:
The antidiabetic activities of the aqueous (AqEx) and ethanolic (AlEx) extracts of Cleome droserifolia
(Forssk.) Del., were tested in cultured C2C12 skeletal muscle cells and 3T3-L1 adipocytes. An 18-h treatment with the AqEx increased basal glucose uptake by 33% [insulin equivalent (IE) = 1.3 ± 0.04] in muscle
cells comparable to a 25.5% increase caused by 100 nM insulin (IE = 1 ± 0.03). Fractionation of the tested
AqEx yielded hexane (HxFr), chloroform (ClFr) and ethyl acetate (EtFr) fractions which exerted 38, 52 and
35% increase in the glucose uptake corresponding to an IE of 1.5 ± 0.06, 2.0 ± 0.04 and 1.4 ± 0.04, respectively. Only the ClFr and EtFr accelerated the triglyceride accumulation [rosiglitazone equivalent(RE) was
0.9 ± 0.13 and 0.63 ± 0.12, respectively] in pre-adipocytes undergoing differentiation comparably with
10 M rosiglitazone. Six terpenoids (C1–C6) and three flavonol glycosides (F1–F3) were isolated from the
active ClFr and EtFr, respectively, and identified. C5, C2 and C4 had an IE of 0.86 ± 0.05, 1.01 ± 0.04 and
0.9 ± 0.08, while F1, F2 and F3 gave an IE of 1.3 ± 0.05, 2.3 ± 0.05 and 2.0 ± 0.04, respectively. We could
conclude that the reported antihyperglycemic activity of Cleome droserifolia is attributed to significant
insulin-like effects in peripheral tissues, and that compounds F2 and F3, being highly active, could be
used as bioactive markers to standardize the C. droserifolia herbal extract.