Characterization, Antioxidant and Antibacterial Potentials of Tamarindus indica L. Fruit Pulp Extract Loaded O/W Nanoemulsions

Abstract The main purposes of the current study were to formulate o/w nanoemulsions as a carrier for Tamarindus indica (tamarind) fruit pulp extract and to study the antioxidant and antibacterial potentials of nanoemulsions containing tamarind extract, focusing on cosmetic/hygiene applications. The o/w nanoemulsions using a mixture of Tween 80 and Span 80 as an emulsifier (5%w/w) were prepared by a high pressure homogenization process. Two concentrations of sweet tamarind extract, 3.3 and 6.6%w/w, based on the bioactivity study, were incorporated into the blank nanoemulsions to produce loaded nanoemulsions, F1-3.3TE (3.3%) and F1- 6.6TE (6.6%). As compared with the unloaded nanoemulsion, both tamarind extract loaded nanoemulsions showed reduced pH and significantly increased viscosity. Overall, the loaded nanoemulsions had droplet sizes of approximately 130 nm, zeta potential around -38 mV and polydispersity index (PDI) values less than 0.2. The nanoemulsion F1-3.3TE had better stability (e.g. significantly greater % tartaric acid content and lesser PDI value) than the nanoemulsion F1-6.6TE did. The antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl assay revealed that the nanoemulsions F1-3.3TE and F1-6.6TE had scavenging activities of 81.66 ± 0.77% and 63.80 ± 0.79%, respectively. However, antioxidant activity of these two formulations decreased under stress conditions (heating-cooling cycles). Such incidence did not occur for their antibacterial properties investigated by agar well diffusion technique. The two formulations exhibited inhibition zones of approximately 24.0-27.7 mm against Staphylococcus aureus and Staphylococcus epidermidis, responsible for malodor of underarms. The results suggest the potential of using sweet tamarind pulp extract loaded nanoemulsions as hygiene products.

A Cold Process Preparation of Vetiveria zizanioides (L.) Nash Oil Lotions using Simulgel FL as an Emulsifier.

Vetiveria zizanioides (vetiver) contains viscous volatile oil, which has the ability to repel mosquitoes similar to citronella oil, a well-known mosquito repellent in tropical countries, like Thailand. The objectives of the current study were to formulate the stable oil-in-water vetiver oil lotions using Simulgel FL as a liquid emulsifier, to investigate the physicochemical properties of the prepared lotions and to evaluate the in vitro release characteristics of the stable vetiver oil lotions. In this work, the concentrations of Simulgel FL ranged from 1% to 3% weight in weight, whereas the concentrations of vetiver oil were varied: 2.5%, 5%, and 10% weight in weight. The suitable concentration of Simulgel FL was found to be 3% weight in weight. For comparison purposes, oil-in-water citronella oil lotions (10% weightin- weight citronella oil) were also prepared with similar ingredients. A mixture of vetiver oil and citronella oil (1:1 by weight) was also used as an active ingredient. By using Simulgel FL, the lotions could be prepared using a cold process (without heat). The physicochemical properties (appearance, pH, viscosity) of the stable lotions were satisfactory. All prepared lotions possessed weak acidic pH values with pseudoplastic flows. Using modified Franz diffusion cell and synthetic membrane, the release rates of vetiver oil were relatively lower than those of citronella oil.

Effects of glucam P-20, vanillin, and fixolide on mosquito repellency of citronella oil lotions.

The objective of this study was to investigate the effects of three fragrance fixatives, Glucam P-20, Vanillin, and Fixolide, on the mosquito repellent property of citronella oil lotions. In the current study, two formulae (A and B) of oil-in-water citronella oil lotions were formulated using different ingredients (emulsifiers [Cremophors or Emulwax], stiffening agents, and emollients). Citronella oil was used at 10% wt:wt. The weight ratios tested between citronella oil and each fixative were 1:0.25, 1:0.5, and 1:1. Overall, 20 formulations, including one with no fixatives for both A and B, were produced, A1-A10 and B1-B10. The repellent activities of these 20 lotions against Aedes aegypti (L.) were tested using a human-bait technique. The types and concentrations of fixatives as well as the compositions of the formulations did affect the protection time of the citronella oil lotions. The lotion containing Emulwax and 5% vanillin (B6) was the most effective repellent. It provided the longest protection time of 4.8 h, which exceeded the minimum requirement of 2 h set by the National Institute of Health, Thailand. The shortest protection time (1 h) was observed in the lotion containing Emulwax and 2.5% Glucam P-20 (B2). It could be concluded that the tested fixatives affected the repellent activity of the citronella oil lotions.