Screening of total thiosulfinates and hydrogen sulfide levels in garlic specimens cultivated in different environmental conditions

Abstract

Pharmacological potency of organic sulfur compounds revived the interest of garlic consumption, particularly by the discoveries about their involvement in suppressing the secretion of proinflammatory cytokines, therefore providing successful prevention against COVID-19. Hence, the aim of our study was to assess the differences in thiosulfinate and H2S content in different parts from three garlic specimens, influenced by different extractants. Wild garlic was found as the richest source of bioactive compounds (4.09 mg GAE/g and 5.11 mg QE/g for phenol and flavonoid content in ME) which contributed to its high 2,2-Diphenyl-1-picrylhydrazyl and NO scavenging rates (⁓70% and ⁓50%, respectively, at 100 mg/ml), reducing power and enzyme activity. Higher H2S content was detected in leaves (1.47–1.76 µmol/g FW), which inversely correlates with thiosulfinates as its source. Additionally, H2S maintained higher value of reducing sugars in leaves (88.19% of total carbohydrates), highlighting its protective role in delaying the process of senescence. Practical applications Targeting the tissue-specific distribution of bioactive components in different garlic specimens, with particular interest in the thiosulfinate content and its stability, its conversion to H2S will provide a valuable insight about the therapeutic properties of garlic, highlight novel understandings about the vasoactive effects, thus inviting additional in vivo research with isolated H2S donors. Differences in the antioxidant potencies on account of the environmental factors and cultivation sites could also contribute to exposing high-quality garlic specimens.