Comparative Phytochemical Profiling (GC-MS and HPLC) and Evaluation of Antioxidant Activities of Wild, In Vitro Cultured and Greenhouse Plants of Kaempferia grandifolia Saensouk and Jenjitt and Kaempferia siamensis Sirirugsa; Rare Plant Species in Thailand

Background Kaempferia grandifolia and Kaempferia siamensis are rare plant species in Thailand used for medicinal, food, and ornamental purposes. Objectives To compare the phytochemical profiles of leaf and rhizome extracts from wild, in vitro culture, and greenhouse plants of K. grandifolia and K. siamensis. Materials and Methods Leaf and rhizome were extracted and analyzed phytochemically by high-performance liquid chromatography (HPLC), gas chromatography mass spectrometry (GC-MS), total phenolic contents (TPC), and total flavonoid contents (TFC). Antioxidant activities were examined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2 '-azinobis(3-ethylbenzothiazoline6-sulfonic acid) diammonium salt (ABTS) assays. Results The results of HPLC analysis showed that the main compounds found in all plants were p-coumaric acid, ferulic acid, and quercetin. GC-MS results revealed 38 compounds in K. grandifolia and 19 compounds in K. siamensis. Major constituents in the leaf and rhizome extracts were 9-octadecenamide, (Z)-, hexadecanamide, and octadecanamide. Total phenolic and total flavonoid contents of leaf extracts decreased from wild to in vitro cultured and greenhouse plants, respectively, whereas rhizome extract contents increased from wild to greenhouse plants. Antioxidant activities of rhizome extracts showed higher activity than leaf extracts in DPPH and ABTS assays. Conclusion The present research is the first report to study the phytochemical profiles and antioxidant activities of these plants. Rhizome extracts of K. grandifolia and K. siamensis in greenhouse plants presented the highest phenolic and high free radical scavenging activity compared to rhizome extracts of wild plant. The phytochemical profiles of the compounds found in the K. grandifolia and K. siamensis extracts showed that these plants have potential for future health benefits.