Ursane-Type Triterpenes, Phenolics and Phenolic Derivatives from Globimetula braunii Leaf.

Ayodeji Oluwabunmi Oriola,Temilolu Idowu,Thomas Oyebode Idowu,Adetunji Joseph Aladesanmi,Adebola Omowunmi Oyedeji,Florence O Akinwumi,Efere Martins Obuotor

doi:10.3390/molecules26216528

Ayodeji Oluwabunmi Oriola, Temilolu Idowu + Show 5 more

Open Access

https://doi.org/10.3390/molecules26216528

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Abstract

Globimetula braunii is a hemi-parasitic plant used in African ethnomedicine for the management of microbial infections, rheumatic pain and tumors amongst others. We report the isolation and characterization of eight compounds with their antioxidant and antimicrobial activities. The air-dried powdered leaf was macerated in EtOH/H20 (4:1). The extract was solvent-partitioned into n-hexane, EtOAc, n-BuOH and aqueous fractions. The fractions were screened for their antioxidant properties, using DPPH, FRAP, TAC and FIC assays. Antimicrobial analysis was performed using the micro-broth dilution method. The active EtOAc fraction was purified for its putative compounds on a repeated silica gel column chromatography monitored with TLC-bioautography. The isolated compounds were characterized using spectroscopic methods of UV, FT-IR, NMR and MS. Eight compounds (1–8) were isolated and characterized as 13,27-cycloursane (1), phyllanthone (2), globraunone (3), three phenolics: methyl 3,5-dihydroxy-4-methoxybenzoate (4), methyl 3-methyl-4-hydroxybenzoate (5) and guaiacol (6), as well as two phenol derivatives: 4-formaldehyde phenone (7) and 6-methoxy-2H-inden-5-ol (8). The study identified 4 and 6 as natural antioxidant compounds with potential as antimicrobial agents.

Highlights

Globimetula braunii (Engl.) Van Tiegh. (Family Loranthaceae) is a hemi-parasitic and epiphytic plant that derives water and mineral nutrients from its hosts by means of a specialized root system called “haustorium” [1]
G. braunii is implicated in the African ethnomedicine for the management of microbial infections, wounds, cholera, hypertension, diabetes, rheumatism, ulcers and tumors [3,5,6]
For the first time, the bioactivity-guided isolation and characterization of three ursane-type triterpenes, three phenolics and two phenol derivatives from the leaf of

Summary

Introduction

Globimetula braunii (Engl.) Van Tiegh. (Family Loranthaceae) is a hemi-parasitic and epiphytic plant that derives water and mineral nutrients from its hosts by means of a specialized root system called “haustorium” [1]. (Family Loranthaceae) is a hemi-parasitic and epiphytic plant that derives water and mineral nutrients from its hosts by means of a specialized root system called “haustorium” [1]. It produces reddish to reddish brown inflorescence with yellow patches in the form of a match sticks. It is widely distributed across tropical West African countries, such as Nigeria, Ghana, Benin Republic and Cameroun [4]. G. braunii is implicated in the African ethnomedicine for the management of microbial infections, wounds, cholera, hypertension, diabetes, rheumatism, ulcers and tumors [3,5,6]

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