Identification of two kinds of Colchicum corms by DNA barcoding, physicochemical, chromatographic and chemometric analyses along with pharmacognostic parameters

Abstract

Corms of “Suranjan” are widely used in traditional medicine for the management of rheumatism and various ailments. In traditional medicinal systems of India, Suranjan is divided into two categories, i.e. “Suranjan Talkh”, which is known as “Bitter Suranjan” and “Suranjan Shirin”, which is known as “Sweet Suranjan”. There is confusion between both species even though both have the same genus, i.e. Colchicum. In the present study, DNA barcoding, pharmacognostic parameters, chromatographic analysis (including HPTLC, HPLC, LC-MS and GC–MS) and a safety parameter and multivariant analysis was performed to identify the corms of both species. DNA barcoding-based results indicated that the bitter species is Colchicum luteum Baker whereas the sweet species is Colchicum autumnale L. Chemical profiling revealed that colchicine is a basic biomarker of both varieties. Moreover, based upon HPTLC and HPLC analyses, the major difference is that Colchicum autumnale L. contained caffeic acid along with colchicine. The phytochemicals observed in HPTLC and HPLC analyses was confirmed by LC-MS analysis. More interestingly, Colchicum autumnale L. had 27.34 % more colchicine as compared to Colchicum luteum Baker. As per organoleptic evaluation, Colchicum autumnale L. has a sweeter taste as compared to Colchicum luteum Baker. GC–MS analysis revealed that Colchicum autumnale L. had 90.87 % more melezitose as compared to Colchicum luteum Baker. Melezitose is a non-reducing trisaccharide sugar molecule and considered as a masking agent in the food industry and a replacement for sugar. Melezitose is the molecule that suppresses an unpleasant taste or sensation, i.e. organoleptic parameters. For the HPLC method-based sugar analysis, the observed sucrose content was 130.66 mg/mL in Colchicum autumnale L, whereas no sugar content was observed in Colchicum luteum Baker. Hence, Colchicum autumnaleL.is the sweet variety even in the presence of a high content of colchicine having low bitterness or sweetness due to the presence of Melezitose in a large content. Antioxidant studies (like TPC, TFC and DPPH assays) demonstrated that Colchicum autumnale L. has far better antioxidant activities than Colchicum luteum Baker. In conclusion, the present study may be a breakthrough for the authentication and identification of market samples of Colchicum autumnale L. and Colchicum luteum Baker. Newly established (as per ICH guidelines) HPTLC and HPLC based methods may help analysts to quantify caffeic acid along with colchicine content.