The Kirsten rat sarcoma (KRAS) oncoprotein has been on drug hunters list for decades now. Initially considered undruggable, recent advances have successfully broken the jinx through covalent inhibition that exploits the mutated cys12 in the switch II binding pocket (KRASG12C). Though this approach has achieved some level of success, patients with mutations other than cys12 are still uncatered for. KRASG12D is the most frequent KRAS mutated oncoprotein. It is only until recently, MRTX1133 has been discovered as a potential inhibitor of KRASG12D. This study seeks to unravel the structural binding mechanism of MRTX1133 as well as identify potential drug leads of KRASG12D based on structural binding characteristics of MRTX1133. It was revealed that MRTX1133 binding stabilizes the binding site by increasing the hydrophobicity which resultantly induced positive correlated movements of switches I and II which could disrupt their interaction with effector and regulatory proteins. Furthermore, MRTX1133 interacted with critical residues; Asp69 (− 4.54 kcal/mol), His95 (− 3.65 kcal/mol), Met72 (− 2.27 kcal/mol), Thr58 (− 2.23 kcal/mol), Gln99 (− 2.03 kcal/mol), Arg68 (− 1.67 kcal/mol), Tyr96 (− 1.59 kcal/mol), Tyr64 (− 1.34 kcal/mol), Gly60 (− 1.25 kcal/mol), Asp12 (− 1.04 kcal/mol), and Val9 (− 1.03 kcal/mol) that contributed significantly to the total free binding energy of − 73.23 kcal/mol. Pharmacophore-based virtual screening based on the structural binding mechanisms of MRTX1133 identified ZINC78453217, ZINC70875226 and ZINC64890902 as potential KRASG12D inhibitors. Further, structural optimisations and biochemical testing of these compounds would assist in the discovery of effective KRASG12D inhibitors.

Adhatoda vasica (also called Vasaka) is a traditional medicinal herb used traditionally for the relief of cough, asthma, nasal congestion, bronchial inflammation, upper respiratory infections, bleeding disorders, skin diseases, leprosy, tuberculosis, diabetes, allergic conditions, rheumatism, tumor, and many more diseases. The present study aims to investigate the biological activities of vasicine, a potent alkaloid from A. vasica with different biological/ pharmacological assays and in silico techniques. Vasicine showed antimicrobial activity as evidenced fromthe colony-forming unit assay. It showed antioxidant activity in ABTS scavenging assay (IC50 = 11.5 μg/ml), ferric reducing power assay (IC50 = 15 μg/ml), DPPH radical scavenging assay (IC50 = 18.2 μg/ml), hydroxyl radical scavenging assay (IC50 = 22 μg/ml), and hydrogen peroxide assay (IC50 = 27.8 μg/ml). It also showed anti-inflammatory activity in proteinase inhibitory assay (IC50 = 76 μg/ml), BSA method (IC50 = 51.7 μg/ml), egg albumin method (IC50 = 53.2 μg/ml), and lipooxygenase inhibition assay (IC50 = 76 μg/ml). Vasicine showed antidiabetic activity in α-amylase inhibition assay (IC50 = 47.6 μg/ml), α-glucosidase inhibition assay (IC50 = 49.68 μg/ml), and non-enzymatic glycosylation of hemoglobin assay. It showed antiviral activity against HIV-protease (IC50 = 38.5 μg/ml). Vasicine also showed anticancer activity against lung cancer cells (IC50 = 46.5 μg/ml) and human fibroblast cells (IC50 = 82.5 μg/ml). In silico studies revealed that similar to the native ligands, vasicine also showed a low binding energy, i.e., good binding affinity for the active binding sites and interacted with α-amylase (-6.7 kcal/mol), α-glucosidase (-7.6 kcal/mol), cyclooxygenase (-7.4 kcal/mol), epidermal growth factor receptor (-6.4 kcal/mol), lipooxygenase (-6.9 kcal/mol), and HIV-protease (-6.4 kcal/mol). The present study ascertains the potential of vasicine as a bioactive compound isolated from A. vasica having therapeutic usefulness in many human diseases.