Date Posted: July 20, 2026

Author/s: Jaquelene Ysabel M. Olavere, Alyanna Marie F. Calderon, Alissa Rose M. Hindap, Cecilia P. Lopez, Alain Don S.P. Malvas, Renato I. Dalmacio, RPh, MSPharm., Jebb Patrick M. Delos Santos, RPh, MPH

Background: Diabetes mellitus is one of the leading causes of death in the Philippines and is projected to affect 7.5 million people by 2045 if left unmanaged. Flavonoid-rich foods include fruits, vegetables, grains, legumes and nuts. Most of the studies focused on fruits, vegetables and grains, while other edible kernels were unexplored, but research is limited on the antioxidant and glucose-lowering properties of polyphenol-rich extracts from the Anacardium occidentale (cashew), Arachis hypogaea (peanut), and Canarium ovatum (pili nut). Exploring this underutilized plant part from these nuts could provide innovative solutions for diabetes management.

Objective: This study aimed to assess the antioxidant and glucose-lowering properties of the semipurified extracts of cashew, peanut and pili nut pericarps; identifying which had the highest potential as a natural therapeutic agent.

Methods: Kernel pericarps were extracted by the maceration method using 70% ethanol. The ethanolic extract was subjected to phytochemical screening, and then it was semi-purified into flavonoids through liquid-liquid extraction. The concentration of flavonoid was analyzed through a colorimetric method using a UV-Vis Spectrophotometer and compared to Quercetin (reference standard). Antioxidant activity was assessed using the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) Radical Scavenging Assay compared to Ascorbic Acid (Positive Control), while glucoselowering properties were evaluated through the α-Amylase inhibition assay and compared to Acarbose (positive control).

Results: The result showed that there is no significant difference in the antioxidant property between Ascorbic Acid and A. occidentale (cashew) (p>0.711). Furthermore, there is a very significant difference between Acarbose and cashew in α-Amylase inhibition (p<0.001). C. ovatum (pili nut) displayed the highest α-Amylase inhibition (32.99%) and moderate flavonoid content.

Conclusion: This study demonstrated that cashew exhibited the highest antioxidant property, while pili nut exhibited the highest α-amylase inhibition activity, highlighting their potential for nutraceutical and pharmacological applications in diabetes management.

Keywords: flavonoids, antioxidant, α-amylase