Dereplication of Oligostilbenes in The Crude Extracts of Dipterocarpaceae Plants from Kadamaian, Sabah

Abstract

Oligostilbenes are a class of polyphenolic compounds with notable bioactivities, predominantly produced by Dipterocarpaceae, a major tree family in Southeast Asian tropical rainforests. Given their ecological and pharmacological significance, efficient identification of oligostilbenes from natural sources is essential, particularly to avoid re-isolation of known compounds. This study aimed to apply an LC-ESI-MSⁿ-based dereplication approach for the rapid identification of known oligostilbenes directly from crude extracts of Dipterocarpaceae species collected from Kadamaian, Sabah. The selected species; Parashorea tomentella, Dryobalanops lanceolata, Dipterocarpus caudiferus, Shorea xanthophylla, and Shorea seminist, represent ecologically important flora from one of the most biodiverse forest regions in Malaysia. An in-house MS¹–MS⁵ spectral database of authenticated oligostilbenes was used to match fragmentation profiles and retention times from ten crude extracts (bark and heartwood). A total of 11 known oligostilbenes were confidently identified, with species-and tissue-specific variations observed in their distribution. P. tomentella showed the richest profile in bark, while certain trimeric and tetrameric stilbenes were more prevalent in heartwood, suggesting tissue-specific biosynthetic patterns. Additionally, several unidentified peaks with consistent stilbene-like fragmentation were detected, indicating the presence of potentially novel oligostilbenes. This dereplication method significantly enhanced the speed and reliability of compound identification in complex matrices, demonstrating its utility in streamlining phytochemical workflows. The findings also provide valuable chemotaxonomic insights into the Dipterocarpaceae of Sabah and support their potential as reservoirs of bioactive natural products.