Key points are not available for this paper at this time.
The present study investigates the phytochemical composition, antioxidant potential, and hypoglycemic efficacy of topical Citrullus colocynthis (bitter apple) fruit extract in individuals with type 2 diabetes mellitus (T2DM). The fruit extract, obtained through solvent extraction and analyzed via Gas-Liquid Chromatography (GLC), revealed a high concentration of bioactive compounds, notably terpinene (16.58 %), camphor (12.25 %), p-cymene (8.46 %), limonene (7.12 %), and saponins (9.58 %), contributing to a total identified component concentration of 71.41 %. The extract demonstrated strong antioxidant activity, with DPPH and ABTS radical scavenging assays showing up to 77.04 % and 76.97 % inhibition, respectively, and an Oxygen Radical Absorbance Capacity (ORAC) peaking at 574.82 μmol TE/g extract. Interestingly, metal chelating activity followed an inverse trend, with the highest activity observed at the lowest concentration (25 μL), likely driven by low-molecular-weight phenolics and flavonoids with high bioavailability. A clinical trial involving 36 T2DM patients revealed a significant reduction in blood glucose levels following topical application of the extract to the feet. Blood glucose decreased by 46–65 mg/dL per application, with average values dropping from 157 mg/dL to 99.67 mg/dL (minimum) and from 374.67 mg/dL to 321.33 mg/dL (maximum), irrespective of gender. These findings demonstrate that C. colocynthis extract, rich in terpenes, saponins, phenolics, and flavonoids, exhibits potent antioxidant and hypoglycemic properties, supporting its potential as a safe, effective, and complementary therapeutic approach for managing type 2 diabetes. However, due to the open-label, single-arm design of this pilot study, placebo effects cannot be excluded, and the results require confirmation in randomized, double-blind, placebo-controlled trials.
Alsalihi et al. (Wed,) studied this question.