Development of nanoemulsion incorporated with Hibiscus sabdariffa for cosmeceutical application

Hibiscus sabdariffa (HS) has been reported to possess a crucial content of bioactive compounds, such as phenolic acids and flavonoids, therefore, HS was recognized as a source of antioxidants. Due to that, the development of nanoemulsion incorporated with HS appears promising for cosmeceutical application. This study is focused on the formulation of oil-inwater (O/W) nanoemulsions of HS to enhance the bioaccessibility of its active compounds. The influences of hydrophiliclipophilic balance (HLB) value of surfactant and grapeseed oil (GSO) to olive oil (OO) ratio on the droplet size, zeta potential, PDI and stability of the nanoemulsions were investigated. The results showed that the smallest particle size was obtained at 145.9 nm with PDI = 0.388 and zeta-potential = -41.1 mV in the systems prepared using HLB value of 12 and 2:1 ratio of GSO to OO. Then the selected nanoemulsion which based on the lowest particle size (NE-F6, GSO:OO = 2:1, and HLB = 12) showed good stability over time and temperature without no phase separation, creaming or cracking was spotted. The pH value of the NE-F6 was obtained at 5.2

Development of nanoemulsion incorporated with Hibiscus sabdariffa for cosmeceutical application

Hibiscus sabdariffa (HS) has been reported to possess a crucial content of bioactive compounds, such as phenolic acids and flavonoids, therefore, HS was recognized as a source of antioxidants. Due to that, the development of nanoemulsion incorporated with HS appears promising for cosmeceutical application. This study is focused on the formulation of oil-inwater (O/W) nanoemulsions of HS to enhance the bioaccessibility of its active compounds. The influences of hydrophiliclipophilic balance (HLB) value of surfactant and grapeseed oil (GSO) to olive oil (OO) ratio on the droplet size, zeta potential, PDI and stability of the nanoemulsions were investigated. The results showed that the smallest particle size was obtained at 145.9 nm with PDI = 0.388 and zeta-potential = -41.1 mV in the systems prepared using HLB value of 12 and 2:1 ratio of GSO to OO. Then the selected nanoemulsion which based on the lowest particle size (NE-F6, GSO:OO = 2:1, and HLB = 12) showed good stability over time and temperature without no phase separation, creaming or cracking was spotted. The pH value of the NE-F6 was obtained at 5.2

Phytochemical and antimicrobial activities of different solvent extracts of Hibiscus sabdariffa

The use of plant extracts and phytochemicals with known antimicrobial properties is becoming commonplace worldwide and gaining great significance for therapeutic uses. Thus, the purpose of the present study is to investigate the effects of numerous extraction solvents (hexane, ethyl acetate, ethanol) on the phytochemical constituents and antimicrobial activities of Hibiscus sabdariffa. Phytochemical screening for saponins, tannins, flavonoids, phenolic and alkaloid compounds revealed that the ethanol and ethyl acetate extracts of Hibiscus sabdariffa contained all the aforementioned phytochemical constituents, for theexception of tannins and alkaloids that were absent in the ethyl acetate extract. Interestingly, the hexane extract did not affordsuch constituents. The ethanol extract exhibited stronger inhibitory activity against Bacillus subtilis (B29), Staphylococcusaureus (S276), Staphylococcus epidermis (S273), Pseudomonas aeruginosa (ATCC 15442) and Escherichia coli (E266) than ethyl acetate extract, but the difference was less evident for the hexane extract of Hibiscus sabdariffa which inhibitedonly B. subtilis, as determined by the paper disc method. Base on the findings, it can be construed that the ethanol and ethylacetate extracts of HS have prospective applications as antimicrobial agent as well as one of the sources of therapeutically useful products

An overview of technologies for immobilization of enzymes and surface analysis techniques for immobilized enzymes

The current demands of sustainable green methodologies have increased the use of enzymatic technology in industrial processes. Employment of enzyme as biocatalysts offers the benefits of mild reaction conditions, biodegradability and catalytic efficiency. The harsh conditions of industrial processes, however, increase propensity of enzyme destabilization, shortening their industrial lifespan. Consequently, the technology of enzyme immobilization provides an effective means to circumvent these concerns by enhancing enzyme catalytic properties and also simplify downstream processing and improve operational stability. There are several techniques used to immobilize the enzymes onto supports which range from reversible physical adsorption and ionic linkages, to the irreversible stable covalent bonds. Such techniques produce immobilized enzymes of varying stability due to changes in the surface microenvironment and degree of multipoint attachment. Hence, it is mandatory to obtain information about the structure of the enzyme protein following interaction with the support surface as well as interactions of the enzymes with other proteins. Characterization technologies at the nanoscale level to study enzymes immobilized on surfaces are crucial to obtain valuable qualitative and quantitative information, including morphological visualization of the immobilized enzymes. These technologies are pertinent to assess efficacy of an immobilization technique and development of future enzyme immobilization strategies

Phytochemical and antimicrobial activities of different solvent extracts of Hibiscus sabdariffa

The use of plant extracts and phytochemicals with known antimicrobial properties is becoming commonplace worldwide and gaining great significance for therapeutic uses. Thus, the purpose of the present study is to investigate the effects of numerous extraction solvents (hexane, ethyl acetate, ethanol) on the phytochemical constituents and antimicrobial activities of Hibiscus sabdariffa. Phytochemical screening for saponins, tannins, flavonoids, phenolic and alkaloid compounds revealed that the ethanol and ethyl acetate extracts of Hibiscus sabdariffa contained all the aforementioned phytochemical constituents, for the exception of tannins and alkaloids that were absent in the ethyl acetate extract. Interestingly, the hexane extract did not afford such constituents. The ethanol extract exhibited stronger inhibitory activity against Bacillus subtilis (B29), Staphylococcus aureus (S276), Staphylococcus epidermis (S273), Pseudomonas aeruginosa (ATCC 15442) and Escherichia coli (E266) than ethyl acetate extract, but the difference was less evident for the hexane extract of Hibiscus sabdariffa which inhibited only B. subtilis, as determined by the paper disc method. Base on the findings, it can be construed that the ethanol and ethyl acetate extracts of HS have prospective applications as antimicrobial agent as well as one of the sources of therapeutically useful products

Response surface methodological approach for optimizing production of geranyl propionate catalysed by carbon nanotubes nanobioconjugates

Terpene esters of short-chain fatty acids are essential oils that have big importance in food, cosmetic and pharmaceutical industries as flavours and fragrances. Geraniol and citronellol are the most important substances. Considering the everincreasing demand for such products, their enzymatic production from natural raw materials by using environmentally friendly and economically attractive processes may prove advantageous. In this contribution, we would like to present an alternative option for the production of geranyl propionate using nanobioconjugates consisting of Candida rugosa lipase adsorbed onto multi-walled carbon nanotubes (CRL-MWCNTs). We investigated the effects of incubation time, temperature, solvent log P and substrate molar ratio, and determined the optimum conditions. The yield of geranyl propionate catalysed by CRL-MWCNTs nanobioconjugates was significantly influenced by two factors, namely, temperature and time of the reaction. Under the optimum reaction conditions of 55 C, solvent n-heptane (log P D 4.0), geraniol to propionic acid molar ratio of 5:1 and reaction time of 6 h, the use of CRL-MWCNTs resulted in 51.3% production of geranyl propionate. Therefore, the investigation revealed that geranyl propionate was successfully synthesized under mild conditions with reasonably high yield within a short period of time. The CRL-MWCNTs nanobioconjugates demonstrated a potential as economical and environmentally smarter biocatalysts for the production of geranyl propionate

A facile enzymatic synthesis of geranyl propionate by physically adsorbed Candida rugosa lipase onto multi-walled carbon nanotubes

In view of several disadvantages as well as adverse effects associated with the use of chemical processes for producing esters, alternative techniques such as the utilization of enzymes on multi-walled carbon nanotubes (MWCNTs), have been suggested. In this study, the oxidative MWCNTs prepared using a mixture of HNO3 and H2SO4 (1:3 v/v) were used as a supportive material for the immobilization of Candida rugosa lipase (CRL) through physical adsorption process. The resulting CRL-MWCNTs biocatalysts were utilized for synthesizing geranyl propionate, an important ester for flavoring agent as well as in fragrances. Enzymatic esterification of geraniol with propionic acid was carried out using heptane as a solvent and the efficiency of CRL-MWCNTs as a biocatalyst was compared with the free CRL, considering the incubation time, temperature, molar ratio of acid:alcohol, presence of desiccant as well as its reusability. It was found that the CRL-MWCNTs resulted in a 2-fold improvement in the percentage of conversion of geranyl propionate when compared with the free CRL, demonstrating the highest yield of geranyl propionate at 6h at 55°C, molar ratio acid: alcohol of 1:5 and with the presence of 1.0g desiccant. It was evident that the CRL-MWCNTs biocatalyst could be reused for up to 6 times before a 50% reduction in catalytic efficiency was observed. Hence, it appears that the facile physical adsorption of CRL onto F-MWCNTs has improved the activity and stability of CRL as well as served as an alternative method for the synthesis of geranyl propionate

Antioxidant activity, total phenolic and chlorophyll content of Keningau grown Cucumis sativus L. at two growth stages

The maturation stage of Cucumis sativus is among the important factors affecting its composition and quality. Hence, this study monitored the differences in total phenolic content (TPC), antioxidant activity, pigment and colour of Keningau-grown cucumbers (Cucumis sativus L.) at two stages of maturities, namely the semi-ripe (SR) and ripe (R). The colourimetric and spectroscopic findings revealed significant differences in the assessed variables (P < 0.05) in the two growth stages except for the pigment. The colour of semi-ripe cucumbers was of lower L* (33.39 ± 4.26) and a* (−10.00 ± 1.74) mean values, while the ripe cucumbers registered the corresponding mean values of 36.71 ± 2.85 and −8.90 ± 1.85. R cucumbers gave a higher mean b* coordinate (16.38 ± 3.16) over the SR ones (14.52 ± 2.52). Compositions of pigments, namely, chlorophyll-a (SR: 4.86 ±0.01 μg/mL, R: 3.55 ± 0.00 μg/mL), chlorophyll-b (SR: 2.12 ± 0.02 μg/mL, R: 1.79, 0.02 μg/mL) and total chlorophyll were higher in SR (6.98 ± 0.02 μg/mL) than R (5.34 ± 0.02 μg/mL) cucumbers, except for the composition of carotenoids (SR: 0.82 ± 0.01 μg/mL, R: 1.78 ± 0.01 μg/mL). The TPC in SR was higher (424.21± 5.32 mg/g) than the R ones (185.51±4.62 mg/g), with the corresponding antioxidant activity (IC50) for SR and R at 157.98 ± 1.57 and 191.66 ± 2.58 μg/mL, respectively. TPC and antioxidant activity between the SR and R cucumbers were negatively correlated (−0.992), which meant that not all phenolic compounds were involved in free radical scavenging