Phytochemical Investigation, Antibacterial And Antioxidant Activities And Molecular Docking And Admet Studies Of Stem Bark Extracts And Isolated Compounds Of Lobelia Rhynchopetalum Hemsl

Abstract

Lobelia Rhynchopetalum, The Giant Lobelia, Is A Plant Endemic To Ethiopia. Its Habitat Is Theafroalpine Climate Of The Bale Mountains And Semien Mountains National Park. Recent Studyshow That It Is Under A Threat Of Climate Change. L. Rhynchopetalum Is Among Plants Traditionallyused By Arsi People For The Treatment Of Wide Array Of Diseases Including Leprosy, Wound, Evileye, Retained Placenta, Diarrhea, Fever, Eye Disease, Rabies And Tumor/Cancer. Considering Theabsence Of Prior Scientific Report That Supports Ethno-Medicinal Uses Of The Stem Bark Of Theplant, This Study Focused On Isolation Of Phytoconstituents, In-Vitro And In-Silico Evaluation Of Theanti-Bacterial Activities As Well As Radical Scavenging Activities Of The Stem Bark Extract Andcomponents Thereof Of L. Rhynchopetalum. In View Of This, The Stem Bark Was Extracted Bymaceration With Methanol And Yielded 70g (20%W/W) Of Extract. The Methanol Extract, Aftersilica Gel Column Chromatography, Afford Two Analogous Polyacetylenic Glycosides Labeled Ascompound 41 And 42. 41 Is A Novel Compound And 42 Is Discovered From The Plant For The Firsttime. The Structure Of 42 Was Elucidated Using 1d Proton And 13c Nmr Techniques Andcomparison With Literature. Nmr Spectral Data Of 42 Appears To Be Similar To A Previously Knownpolyacetylinic Glycoside, Lobetyolin. The Extracts And Isolated Compounds Were Evaluated Fortheir Antibacterial Activity Using Agar Disc Diffusion Against Four Strains Of Bacterial Pathogensincluding E. Coli, P. Aeruginosa, S. Aureus And S. Pyogenes. Results Showed That All Extracts Andisolated Compounds Showed Inhibition Diameter Beyond 9 Mm. Molecular Docking Of Isolatedcompounds Was Done Using Autodock Vina Software. Among The Investigated Ligands Compound42 Exhibited Better Docking Efficiency With Pqsa With Binding Affinity (-7.3kcal/Mol). The Extractand Isolated Compounds Were Also Assessed For Their Radical Scavenging Activity Using Dpphassay. The Compound 42 Displayed Promising Radical Scavenging Activity Of 93% (Ic50 = 7.83).The Antibacterial Activity Presented Herein Supports The Traditional Use Of This Plant Againstbacteria. The Drug Likeness Analysis Exhibited That Compound 41 And 42 Obeyed Lipinski?��?S Rule Offive With Zero Violation. Both Compounds Have Been Shown To Have Good Pharmacokinetics Andbioavailability Characteristics. Hence, The Activities Herein Indicated As The Plant Has Greatpotential As A Remedy For Diseases Caused By Bacteria And Radicals.