Biological screening of herbal extracts and essential oil from Plectranthus species: α-amylase and 5-lipoxygenase inhibition and antioxidant and anti-Candida potentials

Abstract The phenolic compound content, the antioxidant and α-amylase inhibition potentials of different extracts of the Plectranthus amboinicus, P. barbatus and P. ornatus were evaluated. We also evaluated the influence of plant growth and harvest time on the chemical composition of the essential oil (EO) of P. amboinicus, its antioxidant and anti-Candida activities and the α-amylase and lipoxygenase inhibitions. The turbo-extract of P. barbatus showed the greatest phenolic compound content and antioxidant activity. No α-amylase inhibition activity was observed in the analyzed extracts, but the turbo-extraction and refluxing extracts possessed high antioxidant activities. Protected cultivation and morning harvest conditions gave the best antioxidant activities, which was associated to the highest carvacrol content. P. amboinicus EO antioxidant activity could contribute to the reduction of oxidative stress in diabetes. Causal Candida strains of diabetic foot ulcers showed sensitivity to P. amboinicus EO. C. albicans and C. dubliniensis were the most sensitive of the selected Candida strains. Turbo-extracts or refluxing of the three species extracts and the EO of P. amboinicus should be considered as a potential candidate for the management the complications of type 2 diabetes.

Antibiotic activity of Plectranthus ornatus Codd, a Traditional Medicinal Plant

ABSTRACT The dichloromethane extract of Plectranthus ornatus Codd., a tradicional medicinal plant, showed antibiotic activity with minimum inhibitory concentration (MIC) values of 0.4 mg.mL-1 and 100 percent of biofilm inhibition against Staphylococcus aureus strains isolated from animals with mastitis infections. Based on these antibacterial activities, in addition to ethnopharmacological reports from healing men and farmers in Brazil, an herbal soap was produced from this active extract and was tested both in vitro and in vivo. In vivo assays conducted on these herbal soaps led to results similar to those previously conducted with the active extract. These results indicated the great potential of this plant for use as an excipient by preparing herbal antibacterial soaps as an alternative veterinary medicine aimed at controlling bovine mastitis infections on small Brazilian farms.

Estudo anatômico comparado de órgãos vegetativos de boldo miúdo, Plectranthus ornatus Codd. e malvariço, Plectranthus amboinicus (Lour.) Spreng. - Lamiaceae / Comparative anatomical study of the vegetative organs of boldo miúdo, Plectranthus ornatus Codd. and malvariço, Plectranthus amboinicus (Lour.) Spreng. - Lamiaceae

Foi feita uma investigação anatômica dos órgãos vegetativos de Plectranthus ornatus, "boldo miúdo" e Plectranthus amboinicus, "malvariço", da família Lamiaceae. Foram estudados o limbo foliar, pecíolo e caule destas duas espécies. Ambas apresentam limbo foliar com tricomas tectores, com tricomas glandulares pedicelados em P. amboinicus e pedicelados e sésseis em P. ornatus. Justifica-se esta investigação, pelo fato de se tratar de espécies utilizadas, popularmente, como fitoterápico.

An anatomical study of the vegetative organs of Plectranthus ornatus, "boldo miúdo" and Plectranthus amboinicus, "malvariço" was made. Both show non-glandular trichomes on the foliar leaf. In P. ornatus, there are pedunculate glandular trichomes and in P. amboinicus, sessile and pedunculate glandular trichomes. This study is justified by the popular utilization of both species as phytotherapeutic agents.