Chemical profiling of Piper nigrum accessions from the southern Western Ghats in India with discovery of piperine-rich elite genotypes

Piper nigrum (black pepper), a globally significant spice and medicinal crop, has its primary centre of origin in the Western Ghats of India. Despite extensive agronomic studies, direct chemical assessment of piperine variability in its wild accessions remains limited. In this study, thirty wild P. nigrum accessions collected from the southern Western Ghats were analyzed for piperine content in their roots and fruits using high-performance thin-layer chromatography (HPTLC) densitometry. The analyses were performed under standardized conditions (silica gel 60 F 254 plates, pet. ether:acetone 13.5:6.5 v/v; detection at 340 nm). Dried fruits exhibited significant quantitative variation, with piperine contents ranging from 2.90 ± 0.22% to 9.65 ± 0.14% (mean = 6.94 ± 1.84%), while roots contained 0–2.20 ± 0.08%. Four elite genotypes (PN 02, PN 03, PN 19, PN 23) were identified with > 9% fruit piperine and one accession (PN 09) with exceptionally high root piperine (2.20%). These findings provide the first systematic quantification of piperine in natural populations of P. nigrum across its native range, revealing substantial intraspecific chemical diversity. The identified piperine-rich elite genotypes represent valuable genetic resources for quality breeding, metabolic studies, and in situ / ex situ conservation programs aimed at sustaining the genetic wealth of wild black pepper.