Antimicrobial Plant Extracts Encapsulated into Polymeric Beads for Potential Application on the Skin

Abstract

Abstract:In this study, the in vitro bacterial growth inhibition, antioxidant activity and the content in bioactive components of Plectranthus barbatus, P. hadiensis var. tomentosus, P. madagascarensis, P. neochilus and P. verticillatus aqueous extracts were investigated and compared by three extraction methods (infusion, decoction and microwave extractions). The microwave extract of P. madagascariensis showed the higher antimicrobial activity against the Staphylococcus epidermidis strain with a minimum inhibitory concentration of 40 µg/mL. This extract also showed no toxicity in a general toxicity assay and no considerable cytotoxicity against a human keratinocyte cell line. The antioxidant activity of the extracts was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH method), and all showed antioxidant activity. The microwave extract of P. madagascariensis was the one with the highest antioxidant activity (IC 50 value of 41.66 µg/mL). To increase extract stability, the microwave P. madagascariensis extract was then successfully encapsulated into alginate beads with high efficiency. This effective and low-cost strategy seems to be easy to extrapolate to an industrial scale with a future application on the skin. OPEN ACCESSPolymers 2014, 6 480

Antimicrobial screening of Plectranthus madagascariensis and P. neochilus extracts

“…Estas suspensões foram espalhadas sobre uma superfície usando uma zaragatoa estéril. [10,11] Posteriormente, os poços foram feitos no agar com aproximadamente 5,0 mm de diâmetro, com uma pipeta de Pasteur. Em seguida, 50 µL de cada amostra, do controlo negativo (DMSO) e dos controlos positivos (vancomicina, anfotericina B ou norfloxacina) para as bactérias Gram-positivas (S. aureus, E. faecalis, B. subtilis, M. smegmatis e S. epidermidis), Gram-negativa (K. pneumoniae, P. aeruginosa e E. coli) e leveduras (S. cerevisiae e C. albicans), foram adicionados em 10 g of powdered plant material dissolved in 200 mL of the respective solvents.…”

Diospyros cuneata Inhibition of Fusarium oxysporum: Aqueous Extract and its Encapsulation by Ionic Gelation

“…By varying the cross-linking of the polymer and the bead concentration in the bioactive compound, one can control the rate and duration of bioactive compound release in vivo. Alginate beads can protect materials, such as proteins [20], amino acids/peptides [21], hormones or enzymes [22], polyphenols [23], antioxidant plant extracts [24], and antimicrobial plant extracts [25], so that they can be delivered to the target choosen [22]. An effective alternative to protect and scatter the bioactivity of aqueous Diospyros cuneata leaf extracts is through encapsulation.…”

Xanthine Oxidase Inhibitory Activity of a Plectranthus saccatus aqueous extract

“…This genus is often cited for its medicinal properties and is traditionally used to treat gastro-intestinal, respiratory, infectious (such as malaria) or skin disorders (14). Several components of plants from the Plectranthus genus have been isolated and identified and have shown to have different pharmacological activities including antimicrobial (15), antitumor (16) and antioxidant activities (17). In the present work, the uric acid-lowering properties of an aqueous extract of Plectranthus saccatus plant, as well as of its major constituent, were studied.…”

“…Este género é frequentemente citado pelas suas propriedades medicinais, sendo usado tradicionalmente para tratar patologias gasto-intestinais, respirató-rias, infecciosas (tais como malária) ou cutâneas (14). Vários componentes de plantas do género Plectranthus foram já isolados e identificados, e revelaram possuir diferentes atividades farmacológicas incluindo ação antimicrobiana (15), antitumoral (16) e antioxidante (17). Neste trabalho foi realizado um estudo in vitro com o objetivo de explorar a atividade hipouricemiante de um extrato aquoso da planta Plectranthus saccatus e do seu constituinte maioritário, constituindo este trabalho uma abordagem preliminar ao estudo de uma eventual nova aplicação terapêutica desta planta no tratamento da gota.…”