Dimeric glycosylated flavan-3-ol and antimicrobial in vitro evaluation of Trichilia catigua extracts

Abstract

Trichilia catigua is a tree known as "catuaba", widely distributed in Brazil.Studies carried out with T. catigua barks suggest that plant has antidepressant, antidiabetic, antimicrobial, antioxidant, antiviral, and preventive against brain damage. The aim of this work was to isolate and characterize compounds from the semipurified fraction of T. catigua barks, and to conduct microbiological screening against bacteria and fungi. The crude extract (CE) of "catuaba" was produced by turbo extraction with acetone-water, and later, partitioned to yield ethyl-acetate (EAF) and aqueous (AqF) fractions. From AqF the new catechin-3-O-α-L-rhamnoside-(4α→8)-epicatechin was isolated, identified, and described here for the first time. Regarding antimicrobial activity, the extracts presented impressive results, mainly for Vancomycin Resistant Enterococcus faecium (VREfm) with MIC of 156.5 μg/mL. The results suggest that extract of T. catigua could potentially be used as an adjuvant to treatment and is a promising candidate for the development of new antimicrobial drugs. Experimental Plant material and extracts preparationThe Trichilia catigua barks was obtained in Caetité, Bahia, Brazil, in May, 2011 (14°05'35.2"S; 42°34'20.2"W, h=916 m). The voucher specimen was deposited at the Herbarium of the State University of Maringá (HUEM#19434), and was identified by Prof. Dr. Cássia M. Sakuragui. The collection of the plant material was registered with IBAMA-SISBIO under No. 11995-6, May 13, 2016, authentication code 48926652 under the responsibility of J. C. P. Mello. Access to the botanical material was registered by the Sistema Nacional de Gestão do Patrimônio Genético e do Conhecimento Tradicional Associado-SisGen under No. A8B4204.The dried and pulverized T. catigua barks was subjected to turbo-extraction (Ultra-Turrax UTC115KT) with acetone-water (7:3, v/v) at 10% (w/v) for 15 min. Then, the extract was filtered, concentrated under reduced pressure, and lyophilized to obtain the crude extract (CE) (19.5%). The CE was partitioned with ethyl acetate and water (1:1, v/v), to yield the ethylacetate fraction (EAF) (28.0%) and the aqueous fraction (AqF) (72.0%). The fractions were concentrated in a rotary evaporator under reduced pressure, and lyophilized. Determination of total polyphenols and antioxidant capacityThe technique used was the colorimetric method of Folin-Ciocalteu, according Blainski et al. (2013). The procedure was performed to CE, EAF, and AqF in which they were weighed, respectively, 150; 40, and 100 mg. The total polyphenols presented the following values: CE (39.46%±0.17), EAF (62.98%±0.58), and AqF (35.32%±0.22).The antioxidant capacity of CE, EAF, and AqF was measured using the 2,2-diphenyl-1picrylhydrazyl (DPPH) radical, according to Amarowicz et al. (2014), with some modifications.Ascorbic acid was used as a standard of antioxidant activity. The IC 50 were: CE (7.07±0.26), EAF (5.89±0.23), AqF (7.77±0.20), and ascorbic acid (7.21±0.28).

Review on phytochemical constituents of the genus Trichilia and biological activities

“…Trichilia catigua extracts and fractions are also excellent candidates for future research into antiviral, antibacterial, and antifungal medicines. The antibacterial properties of the tannins found in this plant are well recognized [21] .…”

Review on the therapeutic activities of the genus Trichilia

“…Both the crude extract and the fractions showed low toxicity (CC50> 400 ug/ml) and high antiviral effect for all viruses, with inhibitory concentration (IC50 2.44-34.25 ug/ml) for herpesvirus and (IC50 0,67-1.8 µg/ml) for PV-1. Ritter et al (2019), on the other hand, carried out work with crude extract from the bark of Trichlia catigua A. Juss and its fractions of ethyl and aqueous acetate. Its objective was to analyze the antimicrobial action against bacteria and fungi.…”

Strawberries treated with biodegradable film containing plant extracts

“…The four plant species presented have microbial and antioxidant activity substances, such as alkaloids, flavonoids, tannins, glycosides, and terpene. In this way, they become alternatives for controlling spoilage by microorganisms in foods (Dotto et al, 2014;Konaté et al, 2015;Ritter et al, 2021). These phytochemicals can formulate biodegradable films and edible coatings, making these species promising for the food industry (Costa et al, 2019;Pinto Andrade et al, 2018;Rabêlo et al, 2014).…”