Heat stress as an innovative approach to enhance the antioxidant production in Pseudooceanicola and Bacillus isolates

It is well known that the quality and quantity of bioactive metabolites in plants and microorganisms are affected by environmental factors. We applied heat stress as a promising approach to stimulate the production of antioxidants in four heat-tolerant bacterial strains (HT1 to HT4) isolated from Aushazia Lake, Qassim Region, Saudi Arabia. The phylogenetic analysis of the 16S rRNA sequences indicated that HT1, HT3 and HT4 belong to genus Bacillus. While HT2 is closely related to Pseudooceanicola marinus with 96.78% similarity. Heat stress differentially induced oxidative damage i.e., high lipid peroxidation, lipoxygenase and xanthine oxidase levels in HT strains. Subsequently, heat stress induced the levels of flavonoids and polyphenols in all strains and glutathione (GSH) in HT2. Heat stress also improved the antioxidant enzyme activities, namely, CAT, SOD and POX in all strains and thioredoxin activity in HT3 and HT4. While GSH cycle (GSH level and GPX, GR, Grx and GST activities) was only detectable and enhanced by heat stress in HT2. The hierarchical cluster analysis of the antioxidants also supported the strain-specific responses. In conclusion, heat stress is a promising approach to enhance antioxidant production in bacteria with potential applications in food quality improvement and health promotion.

KOMBINASI ASAP CAIR TONGKOL JAGUNG (Zea mays L.) DAN SARI LEMON CUI (Citrus microcarpa) DALAM MENGHAMBAT PEMBENTUKAN PEROKSIDASI LIPID

ABSTRAKPenelitian ini bertujuan untuk mempelajari kombinasi asap cair tongkol jagung dan sari lemon cui dalam menghambat pembentukkan peroksidasi lipid. Penelitian ini menggunakan metode untuk menganalisis kandungan total fenolik, penangkal radikal bebas (DPPH), uji vitamin C dan peroksidasi lipid dengan menggunakan spektrofotometer UV-Vis. Hasil penelitian menunjukkan kandungan total fenolik dari kombinasi asap cair tongkol jagung dan sari lemon F1 (57,94 µg/mL), F2 (82,21 µg/mL), F3 (77,85 µg/mL) F4 (59,94 µg/ mL) dan F5 (93,94 µg/mL). Penangkal radikal bebas (DPPH) kombinasi asap cair tongkol jagung dan sari lemon cui F1 (78,20%), F2 (68,76%), F3 (73,93%) F4 (75,10%) dan F5 (65,75%). Kandungan vitamin C dari kombinasi asap cair tongkol jagung dan sari lemon cui F2 (73,04 µg/mL), F3 (25,25 µg/mL), F4 (183,04 µg/mL) dan F5 (292,16 µg/mL). Kombinasi dari asap cair tongkol jagung dan sari lemon cui dalam penghambat pembentukkan peroksidasi lipid pada ikan cakalang dengan konsentrasi 10% tanpa kombinasi asap cair tongkol jagung dan sari lemon cui menunjukkan peroksidasi lipid yang tinggi yaitu 1,217 dalam empat hari. Kombinasi asap cair tongkol jagung dan sari lemon cui mengandung fenolik yang bertindak sebagai antioksidan dan dapat menghambat peroksidsi lipid pada ikan cakalang. ABSTRACTSersermudy et al., 2019. This research aims to study a combination of corncob liquid smoke and cui lemon juice in inhibiting the formation of lipid peroxidation. This research used a method to analyze the content of total phenolic, free radicidal (DPPH), vitamin C and lipid peroxidation using a UV-Vis spectrophotometer. The results showed a combination of total phenolic from a combination of corncobs and lemon juice F1 57.94 F2 82.21 F3 77.85 F4 59.94 and F5 93.94 μg / mL. Free radical scavenging (DPPH) a combination of liquid corncob and lemon juice cui F1 (78.20%), F2 (68.76%) F3 (73.93%), F4 (75.10%) and F5 (65.75%). Vitamin C content from a combination of liquid corncob smoke and lemon juice cui F2 (73.04 µg/mL), F3 (125.25 µg/mL) F4 (183.04 µg/mL) and F5 (292.16 μg/mL). The combination of corncob liquid smoke and cui lemon juice in the formation of lipid peroxidation in 10% of skipjack tuna without the combination of corn cob liquid smoke and cui lemon juice showed high lipid peroxidation of 1.217 in four days. The combination of corncob liquid smoke and lemon cui juice contains phenolic which acts as an antioxidant and can inhibit lipid peroxidation in skipjack.

Effect of Novel Synthesised Policosanyl Phenolates on Lipid Oxidation

Lipophilic derivatisation of phenolic acids could greatly improve their antioxidant activities and solubility in hydrophobic environments, broadening their applications in food, pharmaceutical, and cosmetic industries. In this study, we conducted enzymatic lipophilisation of eight phenolates with policosanols. Vinyl phenolates were used as intermediates to improve the efficiency of enzymatic lipophilisation; and the yields of policosanyl phenolates were in the range of 1.32–20.58%. The antioxidant activities of the resulting phenolipids were compared using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assay and linoleic acid peroxidation ferric thiocyanate assay. The synthesised policosanyl phenolates showed lower ABTS radical scavenging capacities (IC₅₀s > 15 mM); whereas they showed high lipid peroxidation inhibitory activities (IC₅₀s of peroxidation value < 0.25 mM). The lipid oxidation inhibitory activities of policosanol phenolates were further evaluated using the total oxidation value in a linoleic acid model system and the thiobarbituric acid reactive substances value in a cooked pork model system. Finally, policosanyl 4-hydroxybenzoate, policosanyl syringate, and policosanyl 4-hydroxyphenylacetate showed the highest inhibition effects on lipid oxidation and a potential for use as lipid antioxidants.

Indole Alkaloids from Vinca major and V. minor Growing in Turkey

A new indole alkaloid, 11-hydroxypolyneuridine, was isolated from Vinca major subsp. major L. and the known indole alkaloids vallesiachotamine and isovallesiachotamine from Vinca minor L. This is the first report on the alkaloids of both Vinca species growing in Turkey; vallesiachotamine and isovallesiachotamine were isolated from a Vinca species for the first time. V. minor may be considered as a new source for these two alkaloids due to their occurrence in high amount in the aerial parts of the plant. The alkaloid extracts of the two Vinca species were found to have high lipid peroxidation inhibitory and DPPH radical scavenging activities. Anticholinesterase activity of the extracts was also very strong.