Antioxidant and angiotension-converting enzyme inhibition capacities of various parts of Benincasa hispida (wax gourd)

Vegetables and fruits have been shown to be good sources of antioxidants. Benincasa hispida (wax gourd) has been used in traditional Chinese medicine to treat hypertension and inflammation. The aims of this study were to investigate the abilities of antioxidation and inhibition of angiotensin-converting enzyme (ACE) activity of wax gourd pulp, core, seed and peel prepared by different extraction methods. The fresh weights required to reach 50% inhibition of linoleic acid oxidation were higher in fresh extracts, compared to other extraction methods. Fresh weights required to reach 50% inhibition were the lowest in seed. The seed had the lowest Cu2+-induced low-density lipoprotein (LDL) oxidation percentage and inhibition level of ACE activity among all parts. The higher antioxidant capacity of the seed may result from the higher total phenolics contents and superoxide dismutase activity. The abilities of antioxidation and ACE activity inhibition may provide protective effects against cardiovascular diseases and cancers.