Effects of two medicinal plants Psidium guajava L. (Myrtaceae) and Diospyros mespiliformis L. (Ebenaceae) leaf extracts on rat skeletal muscle cells in primary culture

Crude decoction, aqueous and ethanolic extracts of two medicinal plants (Psidium guajava and Diospyros mespiliformis), widely used in the central plateau of Burkina Faso to treat many diseases were evaluated for their antagonistic effects on caffeine induced calcium release from sarcoplasmic reticulum of rat skeletal muscle cells. These different extracts showed a decrease of caffeine induced calcium release in a dose dependent manner. Comparison of the results showed that Psidium guajava leaf extracts are more active than extracts of Diospyros mespiliformis and that crude decoctions show better inhibitory activity. The observed results could explaine their use as antihypertensive and antidiarrhoeal agents in traditional medicine, by inhibiting intracellular calcium release

Antioxidant and tyrosinase inhibitory activities of different parts of guava (Psidium guajava L.)

10.1007/s10068-011-0148-9Food Science and Biotechnology2041095-110

Microbicidal effect of medicinal plant extracts (Psidium guajava Linn. and Carica papaya Linn.) upon bacteria isolated from fish muscle and known to induce diarrhea in children Uso de extrato de plantas medicinais (Psidium guajava Linn. e Carica papaya Linn.) frente a bactérias isoladas de pescado, causadoras de diarréias infantis

Out of the twenty-four samples of shrimp and fish muscle used for this study, twelve were collected near a large marine sewer for waste disposal, 3 km off the coast of Fortaleza (Brazil) and used for the isolation of E. coli. Other twelve were collected at the Mucuripe fresh fish market (Fortaleza, Brazil) and used for the isolation of Staphylococcus aureus. Ethanol, water and acetone-diluted extracts of guava and papaya leaf sprouts were tested on the bacteria in order to verify their microbicidal potential. The E. coli strains used in the trials were rated LT positive. The papaya leaf extracts (Carica papaya Linn) showed no microbicidal activity while the guava sprout extracts (Psidium guajava Linn) displayed halos exceeding 13 mm for both species, an effect considered to be inhibitory by the method employed. Guava sprout extracts by 50% diluted ethanol most effectively inhibited E. coli (EPEC), while those in 50% acetone were less effective. It may be concluded that guava sprout extracts constitute a feasible treatment option for diarrhea caused by E. coli or by S. aureus-produced toxins, due to their quick curative action, easy availability in tropical countries and low cost to the consumer.<br>Foram coletadas doze amostras de camarão e peixes nas imediações do interceptor oceânico, em Fortaleza e igual número na Feira de pescado do Mucuripe, Fortaleza, para isolamento de E. coli e Staphylococcus aureus, respectivamente. Extratos aquosos, alcoólicos e cetônicos de broto de goiabeira e de folha de mamão foram testados frente às bactérias para se verificar suas ações antibióticas. As cepas de E. coli utilizadas nos ensaios foram as classificadas como LT positivas. Os extratos de folhas de mamão (Carica papaya Linn) não revelaram quaisquer atividades antibióticas enquanto que os preparados com broto de goiabeira (Psidium guajava Linn) apresentaram halos sempre >13 mm para as duas espécies, considerados como de inibição pelo método empregado. Os extratos de broto de goiabeira que apresentaram melhores resultados frente às cepas de E. coli ETEC foram os alcoólicos a 50% seguido do cetônico também a 50%. Concluímos que nos tratamentos de diarréias causadas por E. coli ou por toxinas elaboradas por S. aureus o extrato de brotos de goiabeira é uma opção devido a sua pronta ação curativa, seu fácil cultivo nos países tropicais e ao seu baixo valor aquisitivo