Chemometric guided isolation of new triterpenoid saponins as acetylcholinesterase inhibitors from seeds of Achyranthes bidentata Blume.

Achyranthes bidentata Blume (Amaranthaceae) is an annual or perennial herb widely used as ethnomedicine in Traditional Chinese Medicine for treating fever, cold, ulcers, mensural pain, dementia, and osteoporosis. In the current study, UPLC-IM-Q-TOF-MS/MS-based chemometric approach was adopted for the tentative identification of fifty-six compounds in the extract and fractions of A.bidentata seeds. Further, the chemometric-guided isolation led to the isolation of two previously undescribed oleanane-type triterpenoid saponins, named achyranosides A-B (27 and 30), along with three known compounds (31, 44, and 23) from water fraction of A. bidentata seeds. The structures of new compounds were elucidated based on the detailed analysis of NMR, HR-ESI-MS, FT-IR spectral data, and GC-FID techniques. The isolated compounds in vitro acetylcholinesterase inhibitory activity revealed the promising activity of chikusetsusaponin IVa (23) (IC50 = 63.7 µM) with mixed type of AChE inhibition in enzyme kinetic studies. Additionally, in silico binding free energy of isolated compounds disclosed the greater stability of enzyme-ligand complex owing to underlying multiple H-bond interactions. Overall, the study demonstrates the effectiveness of a chemometric-guided approach for the phytochemical exploration and isolation of new oleanane-type triterpenoid saponins from A. bidentata seeds.

Antiplasmodial activity of the bulbs of Fritillaria cirrhosa D.Don (Syn: Fritillaria roylei Hook.): UPLC-IM-Q-TOF-MS/MS-based biochemometric approach for the identification of marker compounds.

ETHNOPHARMACOLOGICAL RELEVANCE: Fritillaria cirrhosa D.Don (Syn: Fritillaria roylei Hook.) (Hindi name: Kshirakakoli) is a critically endangered Himalayan medicinal plant, well documented in Ayurveda for its therapeutic uses against various disorders such as jvara (fever), kasa (respiratory tract disease) etc. Its bulbs are also used as Szechuan-Pei-Mu for their antipyretic properties in the traditional Chinese medicine. However, despite its ethnomedicinal usage, the therapeutic use of F. cirrhosa bulbs for jvara (fever) related conditions such as malaria has remained unexplored. Hence in the context of increasing global concerns about drug-resistant malaria, it is important to investigate the antiplasmodial activity of F. cirrhosa bulbs for novel antimalarial agents. AIM OF THE STUDY: To investigate the antiplasmodial effects of the extracts/fractions of F. cirrhosa bulbs by the biochemometric approach and to rationalize its ethnopharmacological usage for jvara (fever) related conditions such as malaria. MATERIAL AND METHODS: This study involves the UHPLC-MS-based plant material selection, preparation, quantification, and assessment of F. cirrhosa bulb extracts against CQ-sensitive Pf 3D7 & CQ-resistant Pf INDO strains. Further, UPLC-IM-Q-TOF-MS-based biochemometric approach has been applied for the identification of marker compounds responsible for the observed antiplasmodial effects. The identified marker compounds were also assessed for their in silico ADMET properties and binding efficacy with the drug transporter Pf CRT. RESULTS: Different F. cirrhosa bulb extracts/fractions showed promising antiplasmodial activity with IC50 values 2.71-19.77 µg/mL for CQ-resistant Pf INDO strain and 1.76-21.52 µg/mL for CQ-sensitive Pf 3D7 strain. UPLC-IM-Q-TOF-MS/MS-based biochemometric analysis revealed four marker compounds i.e., peimine (m/z 432.3448), peimisine (m/z 428.3504), puqiedinone (m/z 414.3379), and puqiedine (m/z 416.3509) responsible for the observed antiplasmodial activity. The identified marker compounds showed excellent binding efficacy with Pf CRT and suitable drug-like properties in silico. CONCLUSIONS: The study demonstrated promising antiplasmodial activity of the chloroform and alkaloid enriched fractions of F. cirrhosa bulbs and further identified the four marker compounds responsible for the promising antiplasmodial activity. These marker compounds i.e., peimine, peimisine, puqiedinone and puqiedine were identified by the biochemometric analysis as the putative antiplasmodial constituents of the F. cirrhosa bulbs. Further, in silico studies indicated the good binding affinity of the marker compounds with Pf CRT along with suitable ADMET properties. Overall, the study elucidates the antiplasmodial activity of F. cirrhosa bulbs from the western Himalayan region and provides nascent scientific evidence for their ethnopharmacological usage in jvara (fever) related conditions such as malaria.