Ageratum conyzoides L., recognized globally as a noxious weed, holds significant value in traditional medicine, particularly in treating cuts, wounds, and tick infestations. This study focuses on identifying specific germplasms of this plant, rich in therapeutically valuable metabolites, across various phytogeographical zones in India. Using the Reverse Phase High-Performance Liquid Chromatography with Photodiode Array Detection (RP-HPLC-PDA) method, we analyzed 110 samples to quantify five key bioactive markers: Precocene-I (PRC-I), Coumarin (CM), Caryophyllene (CAR), Caryophyllene Oxide (CAO), and Humulene (HUM). Our findings revealed distinct geographical variations in these compounds. The highest concentrations of PRC-I (7.86±1.36 %) was found in sample NAC-12, CM (1.50±0.46 %) and HUM (0.0099±0.0004 %) in NAC-104, while CAR (6.33±0.87 %) and CAO (6.23±0.18 %) were predominant in NAC-01 and NAC-02, respectively. Ecological Niche Modelling (ENM) was used to predict the climatic suitability of regions for high yield of these metabolites. The ENM results showed that annual precipitation (Bio 12), precipitation of the coldest quarter (Bio 19) and minimum temperature of coldest month (Bio 6) were the principal climatic factors influencing metabolite content. Geographically, the Indo-Gangetic plain, Indus plain, and Central India were identified as suitable for higher content of PRC-I, CAO, CAR, whereas the North Eastern region favoured high content of CM and HUM. This study underscores the importance of bioactive marker-based assessment in understanding chemotypic diversity and demonstrates the effective use of ENM in predicting optimal habitats for harvesting specific chemotypes. These insights pave the way for location-specific cultivation strategies and targeted procurement of metabolite-rich germplasms, contributing to sustainable sourcing and conservation efforts, as well as to the advancement of herbal product standardization and efficacy.

Cassia tora L. is a weed herb and is distributed throughout tropical and subtropical regions of world. Its’ medicinal properties have been described in Indian System of Medicines. Methanolic extracts of seeds from 29 accessions of C. tora were processed using ultrasonication method at room temperature. Emodin and chrysophanol contents in extract were analysed using a reversed phase high performance liquid chromatography - photo diode array detection method. Wide variation in seed extract yield (6.13-19.93%), content of emodin (0.0058 ± 0.002- 0.1002 ± 0.0008 %) and chrysophanol (0.0015 ± 0.0001- 0.182 ± 0.0027 %) of C. tora was recorded. Total phenolics content also showed wide variability in the range of 0.1869 - 0.9375 % in seeds. High emodin content was recorded in C. tora accessions, DCT-4, DCT-14, DCT-10 and DCT-5. Similarly, high chrysophanol content was recorded in accessions DCT-2, DCT-19, DCT-21 and DCT-1. These identified accessions of C. tora can be used for further genetic improvement. RP-HPLC-PDA method developed in the study would also be useful to explore further genetic variability in emodin and chrysophanol contents in C. tora germplasms.

Background: Ageratum conyzoides is an aromatic plant. It is considered as an invasive and cosmopolite weed, widely spread in tropical and subtropical regions. Phytochemicals such as benzopyrenes, flavonoids, and terpenoids are reported from A. conyzoides. Objective: Development and validation of a reversed-phase HPLC-photodiode array (PDA) detection method for simultaneous identification and quantification of coumarin, precocene-I, beta-caryophyllene oxide, alpha-humulene, and beta-caryophyllene in extracts of A. conyzoides and essential oils was carried out. Methods: Separation of analytes was achieved on a RP-18 (250mm x 4.6mm, 5 mu m) column using a solvent system comprising of a mixture of acetonitrile and water with 0.05% trifluoroacetic acid in gradient elution mode at ambient temperature with flow rate of 1mL/min. Results: The retention time of coumarin, precocene-I, beta-caryophyllene oxide, alpha-humulene, and beta-caryophyllene was 4.38, 12.86, 20.10, 33.34, and 35.11min, respectively. Limits of detection for coumarin, precocene-I, beta-caryophyllene oxide, alpha-humulene, and beta-caryophyllene were 2.5, 2.5, 2.5, 0.025, and 2.5 mu g/mL, respectively. Similarly, LOQ were 10, 10, 10, 0.10, and 10 mu g/mL for coumarin, precocene-I, beta-caryophyllene oxide, alpha-humulene, and beta- caryophyllene, respectively. Repeatabilities (RSD, %) values for intraday and interday precision for coumarin, precocene-I, beta-caryophyllene oxide, alpha-humulene, and beta-caryophyllene was 0.765-2.086 and 0.886-2.128; 0.879-1.672 and 0.979-1.825; 0.696-2.418 and 0.768-2.592; 1.728-2.362 and 1.965-2.378; 1.615-2.897 and 1.658-2.906, respectively. Conclusions: The separation of five analytes was achieved within 50min. The developed and validated HPLC-PDA method was successfully applied for identification and quantification of above five analytes in A. conyzoides extracts and essential oils. The method could be used for meeting the characterization criteria of phytoformulations.