Antimicrobial effect and enzymatic activity of extract of Zingiber officinale Roscoe and stability in topical preparations

Os rizomas de Zingiber officinale contem substancias com acao antimicrobiana e enzimas proteoliticas e por essa razao podem ter aplicacoes farmaceuticas. O objetivo deste trabalho foi obter o extrato de rizomas de Zingiber officinale para emprego na area farmaceutica, de forma a preservar a atividade das enzimas proteoliticas presentes, e avaliar tambem sua acao antimicrobiana, visando-se o uso no desenvolvimento de formulacoes topicas. Dois extratos foram obtidos, aquoso e glicolico, que foram avaliados em relacao as suas caracteristicas fisicas, fisico-quimica e organolepticas, alem da sua atividade proteolitica, por meio de reacao de hidrolise enzimica da caseina a 1,2%, em pH 6,0 e a 37oC, utilizando-se papaina como forma de comparacao da atividade. O estudo da acao antimicrobiana do extrato de Zingiber officinale foi realizado por metodo de microdiluicao, utilizando-se Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis e Pseudomonas aeruginosa. Houve ausencia de crescimento de S.aureus e S.epidermidis a partir a concentracao de 150 mg/ml de extrato, enquanto que para P.aeruginosa a partir de 100 mg/ml e para E.coli a partir de 75 mg/ml. Foram elaboradas formulacoes para veiculacao dos extratos, e sua estabilidade foi avaliada. Constatou-se a atividade proteolitica em ambos os extratos, sendo o glicolico superior quanto a manutencao desta atividade, pois o extrato glicolico apresentou 691.68 UP/g e o extrato aquoso 338.14 UP/g. As formulacoes apresentaram estabilidade satisfatoria e o extrato de Zingiber officinale obtido mostrou atividade bactericida frente aos microrganismos testados e sua utilizacao em alimentos, medicamentos e cosmeticos e muito promissora. Palavras-chave: Antimicrobiano. Cosmetico. Enzima. Zingiber officinale. ABSTRACT The rhizomes of common ginger (Zingiber officinale Roscoe) contain substances with antimicrobial activity and proteolytic enzymes and thus may have various pharmaceutical applications. The aim of the present study was to prepare Zingiber officinale Roscoe rhizome extracts for pharmaceutical use, preserving the proteolytic enzyme activity and testing the antimicrobial activity, in order to develop topical formulations. Two extracts were obtained - aqueous and glycolic – and assessed for their physical, physicochemical and organoleptic characteristics. To measure their proteolytic activity, the extracts were assayed for enzymatic hydrolysis of 1.2% casein solution, at pH 6.0 and 37°C; papain was used for comparison. The antimicrobial activity of the glycolic extract of Zingiber officinale Roscoe was tested by microdilution; the inoculants were prepared from cultures of Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa. There was no growth of S. aureus and S. epidermidis at concentrations of 150 mg/mL or more of extract, whereas P. aeruginosa was inhibited from 100 mg/mL and E.coli from 75 mg/mL. Emulsion formulations were prepared as vehicles for the extracts and their stability was tested. The results showed proteolytic activity in both Z. officinale rhizome extracts, the glycolic extract having 691.68 PU/g juice and the aqueous extract, 338.14 PU/g juice. The formulations were stable, especially the one that contained the glycolic extract. In sum, the formulations showed satisfactory stability and the Z. officinale extract showed bactericidal activity against the cultures tested; the results are promising for the use of the extract in foods, medicine and cosmetics. Keywords: Antimicrobial. Cosmetic. Enzyme. Medicine. Zingiber officinale.