Antimicrobial natural products

Our ethnopharmacological studies, in several Angolan regions, showed that Cymbopogon citratus (DC) Stapf., it´s applied in folk medicine to treat several diseases In order to validate antibacterial activity several studies were performed using 12 bacterial strains. The essencial oil samples of Cymbopogon citratus, obtained by hydro-distillation, were analysed by GC and GC-MS. Constituents were identified and tested for their antimicrobial activity by the disc agar diffusion technique and the dilution technique against Staphylococcus aureus (ATCC 25923) and Staphylococcus epidermidis (ATCC 12228) and other bacterial strains. Broad spectrum antibacterial activity was exhibited by the Cymbopogon citratus essential oil against both Gram-positive and Gram-negative bacteria as well as for MRSA that exhibited more sensitive towards the test substance compared to the non-MRSA. Our work was the first to show that Cymbopogon citratus essential oil has higher antibacterial activity against MRSA strains, than commercial antibiotics. These discover opens a new hope to fight against nosocomial infection.info:eu-repo/semantics/publishedVersio

Angolan cymbopogon citratus used for therapeutic benefits: nutritional composition and influence of solvents in phytochemicals content and antioxidant activity of leaf extracts

Folk medicine is a relevant and effective part of indigenous healthcare systems which are, in practice, totally dependent on traditional healers. An outstanding coincidence between indigenous medicinal plant uses and scientifically proved pharmacological properties of several phytochemicals has been observed along the years. This work focused on the leaves of a medicinal plant traditionally used for therapeutic benefits (Angolan Cymbopogon citratus), in order to evaluate their nutritional value. The bioactive phytochemical composition and antioxidant activity of leaf extracts prepared with different solvents (water, methanol and ethanol) were also evaluated. The plant leaves contained ~60% of carbohydrates, protein (~20%), fat (~5%), ash (~4%) and moisture (~9%). The phytochemicals screening revealed the presence of tannins, flavonoids, and terpenoids in all extracts. Methanolic extracts also contained alkaloids and steroids. Several methods were used to evaluate total antioxidant capacity of the different extracts (DPPH; NO; and H2O2 scavenging assays, reducing power, and FRAP). Ethanolic extracts presented a significantly higher antioxidant activity (p < 0.05) except for FRAP, in which the best results were achieved by the aqueous extracts. Methanolic extracts showed the lowest radical scavenging activities for both DPPH; and NO; radicals

Organic versus conventional tomatoes: Influence on physicochemical parameters, bioactive compounds and sensorial attributes

The effect of organic and conventional agricultural systems on the physicochemical parameters, bioactive compounds content, and sensorial attributes of tomatoes (‘‘Redondo’’ cultivar) was studied. The influence on phytochemicals distribution among peel, pulp and seeds was also accessed. Organic tomatoes were richer in lycopene (+20%), vitamin C (+30%), total phenolics (+24%) and flavonoids (+21%) and had higher (+6%) in vitro antioxidant activity. In the conventional fruits, lycopene was mainly concentrated in the pulp, whereas in the organic ones, the peel and seeds contained high levels of bioactive compounds. Only the phenolic compounds had a similar distribution among the different fractions of both types of tomatoes. Furthermore, a sensorial analysis indicated that organic farming improved the gustative properties of this tomato cultivar

Cymbopogon citratus EO antimicrobial activity against multi-drug resistant Gram-positive strains and non-albicans-Candida species

We studied the antibacterial and antifungal activity of Cymbopogon citratus. These properties were studied on hospital isolated multidrug resistant strains Staphylococcus aureus, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumonia and their respective ATCC control strains. Pathogenic Candida albicans, Candida parapsilosis, and Candida tropicalis were also tested. Results of the present investigation provide evidence that the EO of Cymbopogon citratus could have a potential application in the treatment and prevention of diseases caused by Staphylococcus aureus methicillin-resistant strains and by vancomicin-resistant Staphylococcus epidermidis. Cymbopogon citratus EO is also effective against Candida albicans as well as the emerging Candida parapsilosis and Candida tropicalis pointing to its usefulness as an antifungal agent.info:eu-repo/semantics/publishedVersio

Effect of peel and seed removal on the nutritional value and antioxidant activity of tomato (Lycopersicon esculentum L.) fruits

The effect of peel and seed removal, two commonly practiced procedures either at home or by the processing industry, on the physicochemical properties, bioactive compounds contents and antioxidant capacity of tomato fruits of four typical Portuguese cultivars (cereja, chucha, rama and redondo) were appraised. Both procedures caused significant nutritional and antioxidant activity losses in fruits of every cultivar. In general, peeling was more detrimental, since it caused a higher decrease in lycopene, bcarotene, ascorbic acid and phenolics contents (averages of 71%, 50%, 14%, and 32%, respectively) and significantly lowered the antioxidant capacity of the fruits (8% and 10%, using DPPH. and b-carotene linoleate model assays, correspondingly). Although seeds removal favored the increase of both color and sweetness, some bioactive compounds (11% of carotenoids and 24% of phenolics) as well as antioxidant capacity (5%) were loss. The studied cultivars were differently influenced by these procedures. The fruits most affected by peeling were those from redondo cultivar (-66% lycopene, -44% b-carotene, -26% ascorbic acid and -38% phenolics). Seeds removal, in turn, was more injurious for cereja tomatoes (-10% lycopene, -38% b-carotene, -25% ascorbic acid and -63% phenolics). Comparatively with the remaining ones, the rama fruits were less affected by the trimming procedures