Comprehensive analysis of malabar tamarind fruit rind total extract: HPTLC fingerprinting, in-silico exploration of its metabolites for SARS-cov-2 omicron spike protein, antibacterial and antidiabetic potentials with in vitro evaluation of antidiabetic and antioxidant activities.

ABSTRACT

Malabar tamarind tropical fruit, scientifically known as Garcinia gummi-gutta, is indigenous to Southeast Asia. In this work, the total methanolic extract of the Malabar fruit rind was examined by HPTLC fingerprinting, with quantitative evaluation of the total phenolics and flavonoids. Library of previously reported natural metabolites was utilized to demonstrate their affinity for specific target sites, they were evaluated against Omicron SARS-CoV-2 mainly it's Spike Protein, bacterial tyrosinase, and antidiabetic targets such α-glucosidase, pancreatic lipase and also α-amylase enzymes. The molecular docking revealed that the Guttiferone R possessed the highest binding affinity toward the Omicron Spike Protein with a stable binding mode, -8.67 kcal/mol binding energy and a 1.07 Å RMSD value compared to reference, Azithromycin, which has -8.90 kcal/mol binding affinity and a 1.20 Å RMSD value. On the other hand, the identified polyphenolic compounds; Vitexin, Prunin, Naringin, Hinokiflavone, Kaempherol-3-O-rutinoside, Gallic acid, Naringenin, and Catechin, showed remarkable antidiabetic activity by strong inhibitory activity against α-glucosidase and notable activity against α-amylase compared with acarbose as reference. According to antibacterial activity, the identified compounds showed low affinity with weak activity against screened bacterial strains. In-vitro evaluation of Tamarind antioxidant and antidiabetic potentials, it exhibited a free radical-scavenging potential with 71.75 % retardation and α-glucosidase, α-amylase and pancreatic lipase inhibitor activities with an IC50 of 391.3 ± 26.27, 95.03 ± 0.03 and 0.01043 ± 0.0004 µg/mL, respectively that emphasize the molecular docking study. The findings imply that Malabar tamarind fruit rind possess antioxidant, antidiabetic, antibacterial and antiviral activities.