Antioxidant, Antibacterial and Antitumor Activity of Ethanolic Extract of the <i>Psidium guajava</i> Leaves

Abstract

Psidium guajava L. has extensive use in folk medicine. The aim of this study was to quantify the levels of phenolic, flavonoids, antioxidant activity, leathality assay and antibacterial and antitumoral activities of the extract of P. guajava. In the dry guava extract there were high levels of phenolics (766.08 ± 14.52 mg/g), flavonoids (118.90 ± 5.47 mg/g) and antioxidant activity (87.65%). The LD50 was 185.15 µg/ml. The MIC value was 250 µg/ml for Streptococcus mutans, Streptococcus mitis and Streptococcus oralis. IC50 of the extract tested in the HeLa, RKO and Wi cell lines was 15.6 ± 0.8 µg/ml, 21.2 ± 1.1 µg/ml and 68.9 ± 1.5 µg/ml, respectively. The results of all analyses allow us to conclude that the dry extract of guava leaves has promising activity to be applied topically in the oral cavity or in the development of antitumor formulation or even be used as a functional food.

Avaliação da atividade antimicrobiana de extratos de Eugenia anomala e Psidium salutare (Myrtaceae) frente à Escherichia coli e Listeria monocytogenes

“…Pode-se observar que a AA% dos extratos etanólico e de acetato de etila em ambas as espécies vegetais foi maior, onde houve aumento nesta atividade de acordo com o aumento da concentração do extrato analisado, sendo que na maior concentração analisada de 50 µg/mL o extrato (Braga et al, 2014;Castro et al, 2014;Fernandes et al, 2014;Moreno et al, 2014;Seo et al, 2014;Thakur & Arya, 2014).…”

Comparative evaluation of antimicrobial efficacy of an alternative natural agent for disinfection of toothbrushes

“…Although various studies evaluated the efficacy of antimicrobial activity of guava leaves against common oral pathogens,[1011] the present study evaluated its antibacterial efficacy in toothbrushes. The necessity for taking aqueous extracts for the study is because it was aimed to reach the public community for the ease in preparation and as a way to recycle the dried-out leaves of guava.…”

“…The antibacterial activity of guava leaves is attributed to the presence of terpenes,[11] flavonoids,[511] and tannins. [18] Barbalho et al .…”

Hypoglycemic and Antioxidative Effects of <i>Glossogyne tenuifolia</i> on Streptozotocin-Nicotinamide-Induced Diabetic Rats

“…Therefore, many studies have been conducted to find effective inhibitors of α-glucosidase and α-amylase from natural materials and to develop physiological functional food for treating DM [7] [25]. Our results show that inhibition ability of hot water extract (HWGT) for α-glucosidase from yeast were better than that of rat small intestine (p = 0.013).…”

“…Hence, natural products with perceived cost-effectiveness and no long-term side effects but which elicit better antidiabetic activities are highly desired. The health-promoting properties of some herbal teas or Chinese herbal medicines reported to be rich in antioxidants, particularly phenolics and antioxidant vitamins, can exert inhibitory capacities against α-glucosidase and exert hypoglycemic effects [7] [8] [9]. Glossogyne tenuifolia (GT) Cassini, also called Hsiang Ju grass, is a perennial herb with woody stems at the base which is distributed mainly in exposed coastal areas of Penghu Island, Taiwan China.…”