Geographic based phenolic compound variations in South African Schinus molle L. peppercorns

Abstract

Environmental conditions affect polyphenolic compounds in plants, and yet little is known about the response of Schinus molle peppercorns to geographical location. S molle is a folkloric pseudospice of Andean origin possessing multiple culinary and medicinal functions. This globally invasive species presents an immense multidimensional potential. Polyphenolic compounds were therefore profiled and quantified from pink peppercorns growing in 12 distinct locations in the Eastern and Western Cape provinces of South Africa using UPLC-QTOF-MS techniques. Eleven flavonoids were reported, including epigallocatechin gallate, +)-tephrorin B, astilbin, procyanidin B5, 4-benzyl-7-hydroxy-3-phenyl-2H-chromen-2-one, and isochamaejasmin which were reported for the first time in this species. Five phenolic acids, three glycosides, and tannins (theogallin (3-galloylquinic acid), digalloyl quinic acid, digalloylshikimic acid, β-glucogallin A and β-glucogallin B) were also revealed among others. PCA revealed a high composition of polyphenolic compounds in the Eastern in comparison to the Western Cape regions. Flavonoids were glaringly higher in winter rainfall receiving coastal regions. Consequently, the highest catechin content was 229% higher in the Eastern (1269.9 mg/kg) than the Western Cape (553.4 mg/kg). Furthermore, isochamaejasmin, the compound with possibly the highest concentration is reported in George (1741 mg/kg) and Gqeberha (2601.2 mg/kg) representing 149% differences between the two regions. Soil type alone did not conclusively appear to influence polyphenolic compound accumulation in this study. Elucidating the distribution of polyphenolic compounds in this species could open new insights for potential therapeutic, pharmaceutical, and agricultural applications including possibilities for new and improved organic drugs, and food product development. • We report 11 flavonoids, 5 phenolic acids, 3 glycosides, & a coumarin among others. • Mascaroside and verbascoside were newly identified in S. molle peppercorns. • PCA showed that polyphenolic compounds are higher in the Eastern Cape region. • Flavonoid contents are higher in coastal regions experiencing winter rainfall. • Soils alone did not conclusively influence secondary metabolite contents.