Antiobesity Effects of Polyphenolic Enriched Fraction of Alpinia Galanga Rhizomes Through Inhibition of Pancreatic Lipase, Alpha Amylase and 3T3-L1 Adipocyte Differentiation

Background and Aim: Alpinia galanga is an herbal drug widely known in ethno medicine that has been used for centuries to treat kidney disease, tumour, diabetes, bronchitis, gastritis, and other metabolic disorders. Recently, antiobesity properties of A. galanga rhizomes have been designated. The current investigation is aimed to explore the anti-obesity effects of polyphenolic rich fraction of A. galanga rhizomes through the inhibitory action of dietary enzymes and adipocytes.

Methods: In the present study, a methanol extract and its various fractions (hexane, ethyl acetate, chloroform & aqueous) from the rhizomes of A. galanga were prepared and examined for total polyphenolic content (TPC) as well as inhibitory potential of pancreatic lipase and amylase enzymes. Evaluation of antioxidant potential was done using the free-radical scavenging capacity (DPPH) and nitric acid (NO) scavenging. Anti-inflammatory activity was done using albumin denaturation method. Adipocyte dysfunction at cellular level was corrected by examining on cell viability of 3T3-L1 preadipocytes using MTT assay.

Results: Ethyl acetate fraction of A. galanga rhizomes (AGEF) was found to have maximum polyphenol content (353.17 mg GAE/g) and flavonoidal content (91.07 mg/g QE). AGEF also exhibited maximum inhibitory activity against lipase (80.51 %, IC₅₀ value 131.60 μg/ml.) and amylase enzymes (74.74 %, IC₅₀ value 150.20 μg/ml) at 50 50 500 μg/ml. AGEF did not induce any cell death up to 500 μg/ml when examined for cell viability of 3T3-L1 preadipocytes using MTT assay. Oil Red O staining of 3T3-L1 cells showed considerable reduction in adipocyte differentiation and lipid accumulation in the presence of AGEF (500 μg/ml) when compared with untreated 3T3-L1 cells. AGEF also suppressed lipid accumulation and glycerol-3-phosphate dehydrogenase (GPDH) activity without affecting cell viability in 3T3-L1 preadipocytes and adipocytes.

Conclusion: The results indicate the potential of AGEF being useful in mitigating obesity.