Phenotypic and Chemotypic Relations among Local Andrographis paniculata (Burm. f.) Wall Landrace Collection

Abstract

The relationship between the phenotypic and chemical composition of local Andrographis paniculata was evaluated in this study. Five seed collections were sourced from different regions of Thailand, namely Kamphaeng Saen (KS), Udon Thani (UT), Chiang Rai (CR), Chiang Mai (CM), and Ratchaburi (RB). They were cultivated in the same conditions, potted, and partially shaded (60%) in an open conventional greenhouse. The phenology and chemical composition of these plants were assessed at the commercial harvesting stage (ca. 90 days after planting). The results indicated that UT was morphologically distinctive, illustrating the highest edible biomass yield (aerial and mature leaf size). The above-ground parts (viz., leaves and stem) were then analyzed for bioactive compounds after maceration with 80% (w/w) ethanol. It was found that the highest lactone content (~14 mg/g extract) was obtained from leaf and stem extracts of all samples except KS. Nonetheless, total phenolics and flavonoids in the stem extract of KS were found to be the highest at 3.22 and 2.42 mg/g, respectively. Phytochemicals from both leaf and stem extracts were capable of high anti-oxidant activity (~70%) as determined by DPPH and ABTS assays. Chemically, RB contained the highest 14-deoxy-11,12-didehydroandrographolide (156.98 mg/g extract), while UT and CM contained up to 0.68 mg/g extract of neoandrographolide. Classification of the samples indicated a clear relationship between the morphological traits and chemical compositions. In conclusion, our findings suggest the variations in phenotypic and chemotypic relations across the different landraces of A. paniculata. In essence, the quantity of the consumable parts was essentially the marker to describe the quality of the phytochemical constituents. The overall outcome of this study was to select the physiological characteristics that could be used for further breeding programs of the ideal variety with high productivity and higher bioactive(s) content.