Insights from dual-platform metabolomics on durian flowers: An alternative source of procyanidins from agricultural waste with bioactivities

Procyanidins, which are polyphenol compounds in grape seeds, apples, and berries, are known for their anti-inflammatory and antioxidant properties. In this study, we investigated durian flowers, an agricultural waste, as a novel procyanidin source. Durian trees bloom prolifically, but not all flowers develop into mature fruits, representing underutilized resources. Dual-platform metabolomic analysis using ultra-high-performance liquid chromatography with electrospray ionization quadrupole time-of-flight mass spectrometry and gas chromatography-mass spectrometry annotates polyphenols such as (-)-epicatechin, procyanidins B1, B2, and C1. The 80 % (<i>v</i>/v) ethanol extraction yielded a crude extract with a total procyanidin content of 7.68 mg/g. Bioactivity assays revealed that the procyanidin-rich crude extract reduced oxidative stress and exhibited anti-inflammatory effects against UVA in human keratinocytes (HaCaT). This study is the first to propose durian flowers as a sustainable and cost-effective procyanidin source with potential application in the nutraceutical and cosmeceutical industries, contributing significantly to the repurposing of agricultural waste through green technology.