Pesquisa de actividade biológica de sete espécies de Plectranthus
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Data
2017
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Edições Universitárias Lusófonas
Resumo
Os produtos naturais das espécies de plantas Plectranthus têm um uso etnofarmacológico, suscitando vários
estudos científicos. Neste trabalho pretendeu-se validar cientificamente estas plantas, realizando uma pesquisa
de atividades biológicas. Extratos de sete espécies de Plectranthus (P. swynnertonii, P. welwischii, P. woodii,
P. cylindraceus, P. spicatus, P. ramosior e P. petiolaris) foram testados na inibição da acetilcolinesterase in vitro
(AChE), atividades antioxidante e antimicrobiana, e toxicidade em Artemia salina. Os extratos acetónicos foram
obtidos por ultrassons (10% m/v), dos quais P. ramosior obteve o rendimento de extração mais elevado (13,49%
m/m). Todos os extratos foram testados, no entanto apenas o P. cylindraceus obteve inibição da atividade da AChE
(30,2 ± 3,78%). A atividade antimicrobiana foi avaliada usando o método de difusão em poços, contra bactérias
Gram-positivas, -negativas e leveduras. P. ramosior revelou não só inibição contra S. aureus e C. albicans (15 e
11 mm, respetivamente), como também a mais elevada atividade antioxidante (método DPPH, 36,4 ± 0,04%). No
ensaio em A. salina P. swynnertonnii foi o extrato mais tóxico (LC50 = 0,036 mg/L).
Os resultados preliminares obtidos neste trabalho, revelam a potencial biotividade dos extratos de P. cylindraceus,
P. ramosior e P. swynnertonnii, sugerindo o posterior isolamento dos compostos bioactivos, e continuidade dos
estudos antimicrobianos e citotóxicos.
Natural products from Plectranthus spp. plants have an ethnopharmacological use, inspiring several scientific investigations. As such, this work aims to perform a biological activity screening in order to scientifically validate the use of these plants. Assays on in vitro acetylcholinesterase (AChE) inhibition, antioxidant effects, antimicrobial activity and Artemia salina lethality were performed on seven Plectranthus spp. extracts (P. swynnertonii, P. welwischii, P. woodii, P. cylindraceus, P. spicatus, P. ramosior and P. petiolaris). Acetonic extracts were obtained by sonication (10% w/v), where P. ramosior had the highest yield of dry extract (13.49% w/w). In the AChE inhibition assay, only P. cylindraceus extract decreased enzymatic activity (30.2 ± 3.78%). The antimicrobial activity was screened using the well diffusion method, against Gram positive and negative bacteria and yeast. P. ramosior extract showed not only an inhibition zone against S. aureus and C. albicans (15 and 11 mm, respectively), but also the highest scavenging activity (DPPH method, 36.4 ± 0.04%). On the lethality test in A. salina, P. swynnertonnii extract was the most toxic (LC50 = 0.036 mg/L). These preliminary results showed that P. cylindraceus, P. ramosior and P. swynnertonnii are potential bioactive extracts for further isolation and antimicrobial and cytotoxic studies.
Natural products from Plectranthus spp. plants have an ethnopharmacological use, inspiring several scientific investigations. As such, this work aims to perform a biological activity screening in order to scientifically validate the use of these plants. Assays on in vitro acetylcholinesterase (AChE) inhibition, antioxidant effects, antimicrobial activity and Artemia salina lethality were performed on seven Plectranthus spp. extracts (P. swynnertonii, P. welwischii, P. woodii, P. cylindraceus, P. spicatus, P. ramosior and P. petiolaris). Acetonic extracts were obtained by sonication (10% w/v), where P. ramosior had the highest yield of dry extract (13.49% w/w). In the AChE inhibition assay, only P. cylindraceus extract decreased enzymatic activity (30.2 ± 3.78%). The antimicrobial activity was screened using the well diffusion method, against Gram positive and negative bacteria and yeast. P. ramosior extract showed not only an inhibition zone against S. aureus and C. albicans (15 and 11 mm, respectively), but also the highest scavenging activity (DPPH method, 36.4 ± 0.04%). On the lethality test in A. salina, P. swynnertonnii extract was the most toxic (LC50 = 0.036 mg/L). These preliminary results showed that P. cylindraceus, P. ramosior and P. swynnertonnii are potential bioactive extracts for further isolation and antimicrobial and cytotoxic studies.
Descrição
Biomedical and biopharmaceutical research : jornal de investigação biomédica e biofarmacêutica
Palavras-chave
MEDICINA, CIÊNCIAS FARMACÊUTICAS, PLANTAS MEDICINAIS, ANTIOXIDANTES, ANTIMICROBIANOS, TOXICIDADE, MEDICINE, PHARMACEUTICAL SCIENCES, MEDICINAL PLANTS, ANTIOXYDANTS, ANTIMICROBIAL, TOXICITY