ItemArticle

Pollination versus carnivory: functional distribution of naphthoquinones in Nepenthes khasiana

Title
Pollination versus carnivory: functional distribution of naphthoquinones in Nepenthes khasiana
Creator
Lathika, C.C.; Sujatha, G.B.; Sabulal, N.; Johnson, A.J.; Viswanathan, G.; Remadevi, R.K.S.; Shereefa, L.A.; Baby, S.
Description
Nepenthes, a major genus of carnivorous plants, secrete floral and extrafloral nectars (FN and EFN) in their flowers and pitchers, respectively. Recently we demonstrated Nepenthes khasiana EFN as a sugar mix with minimal nitrogenous metabolites and vitamin C. N. khasiana EFN showed insect toxicity due to its strong acetylcholinesterase (AChE) inhibition, and the active principle has been characterized as the naphthoquinone derivative, (+)-isoshinanolone. These findings prompted us to study the chemical composition and toxicity of N. khasiana FN. N. khasiana FN was analyzed for its sugars, amino acids, proteins, fatty acids and vitamin C by HPTLC-densitometry, UFLC, GCMS and biochemical assays. C:N ratio and naphthoquinones were analyzed by CHNS analyzer, headspace-GCMS, and GC-FID, respectively. Toxicity of FN and the naphthoquinone droserone, found in its pitcher fluid, was evaluated using the AChE inhibition assay. N. khasiana FN showed a similar chemical pattern as its EFN, viz., sugar (Glc-Fru-Suc)-mix with minimal amino acids, vitamin C, and moderate protein and fatty acid contents. It showed fairly high C:N ratio. The naphthoquinone, plumbagin, was the major volatile constituent in N. khasiana flowers. Crucially, the AChE inhibitors, (+)-isoshinanolone and plumbagin, were absent in N. khasiana FN, which showed no AChE inhibition. Droserone, however, exhibited strong AChE inhibitory activity. The chemical profiles of EFN and FN reflect a nitrogen-limited metabolism in N. khasiana. Notably, the functional allocation of neurotoxic naphthoquinones abundant in EFN, absent in FN, and present in the pitcher fluid reflects an adaptive strategy that optimizes both nutritional gain through prey capture and reproductive success through pollination. 2026 Wiley-VCH GmbH. Published by John Wiley & Sons Ltd.
Source
Plant Biology;Volume;28;Issue;2;pp.461-467
Date
01-01-2026
Publisher
John Wiley and Sons Inc
Subject
Floral nectar; naphthoquinone distribution; nectar chemistry; Nepenthes; pollination; pollinatorprey conflict; toxicity
Coverage
Lathika C.C., Phytochemistry and Phytopharmacology Division, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Kerala, Pacha-Palode, Thiruvananthapuram, India, Department of Botany, Christian College, Kerala, Kattakada, Thiruvananthapuram, India, University of Kerala, Kerala, Kariavattom, Thiruvananthapuram, India; Sujatha G.B., Phytochemistry and Phytopharmacology Division, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Kerala, Pacha-Palode, Thiruvananthapuram, India, University of Kerala, Kerala, Kariavattom, Thiruvananthapuram, India; Sabulal N., Department of Chemistry, Christ University, Karnataka, Bengaluru, India; Johnson A.J., Phytochemistry and Phytopharmacology Division, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Kerala, Pacha-Palode, Thiruvananthapuram, India; Viswanathan G., Phytochemistry and Phytopharmacology Division, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Kerala, Pacha-Palode, Thiruvananthapuram, India; Remadevi R.K.S., Phytochemistry and Phytopharmacology Division, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Kerala, Pacha-Palode, Thiruvananthapuram, India; Shereefa L.A., Department of Botany, Christian College, Kerala, Kattakada, Thiruvananthapuram, India; Baby S., Phytochemistry and Phytopharmacology Division, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Kerala, Pacha-Palode, Thiruvananthapuram, India
Rights
All Open Access; Bronze Open Access
Relation
ISSN: 14358603; CODEN: PBIOF
Format
online
Language
English
Type
Article

Citation

Lathika, C.C.; Sujatha, G.B.; Sabulal, N.; Johnson, A.J.; Viswanathan, G.; Remadevi, R.K.S.; Shereefa, L.A.; Baby, S., “Pollination versus carnivory: functional distribution of naphthoquinones in Nepenthes khasiana,” CHRIST (Deemed To Be University) Institutional Repository, accessed June 19, 2026, https://archives.christuniversity.in/items/show/22982.

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