Leaves of Allium cepa and Xylopia aethiopica fruits as potent sources of natural antioxidant for stabilization of viscera FISH oil during accelerated storage.

The present study investigated the antioxidant activities of methanolic extracts of two local plants and their capacities to preserve the quality of viscera fish oil during storage. The total phenolic, total flavonoids and tannins contents were analyzed by colorimetry, the preliminary antioxidant tests done and identification of phenolic compounds by HPLC-DAD (Diode Array Detector) and ESI-MS. After these evaluation, the plant extracts were added in viscera fish oil at concentration 200-1000 ppm. The oxidative stability of these fish oil samples was evaluated by measuring their qualities indices during 16 days at 70 °C. Here, oils were collected at the day 0, 4, 8, 12 and 16. The total phenolic, flavonoids and tannins contents in Xylopia aethiopica fruits were 15.62 g Eq acid galic/100g of dry extract, 10.85 mg Eq quercetin/100g of dry extract and 0.79 mg Eq cathechin/100 mg of dry extract. Those of Allium cepa leaves were 6.85 g Eq acid galic/100g of dry extract, 1.50 mg Eq quercetin/100g of dry extract and 0.11 mg Eq cathechin/100 mg of dry extract. All the methanolic extracts exhibited antioxidant activity. The results recorded after FRAP assay revealed the low IC50 (12.87 mg/mL) in Allium cepa extract compared to that of Xylopia aethiopica extract (44.90 mg/mL). These local plants contain many classes of phenolic compounds and they can be used in oil and fat industries as alternative of synthetic antioxidants.

Effect of some local plant extracts on fatty acid composition of fish (Alestes baremoze) during smoking and sun drying in the Far-North region of Cameroon.

The objective of this study was to assess the antioxidant activities of three plant extracts (Moringa oleifera leaves, Xylopia aethiopica fruits, and Allium cepa leaves) and to evaluate their effects on the preservation of fish polyunsaturated fatty acids (PUFAs) during smoking and sun-drying processes. PUFAs are highly prone to oxidation during fish processing. The plant extracts were analyzed for their polyphenol contents and were evaluated for their total antiradical capacity. The polyphenol components of each plant were characterized. The hydroethanolic and aqueous extracts were added to the fish at concentrations of 3, 6, 9, and 12 g/L and 10, 20, 30, and 40 g/L, respectively. Butylated hydroxytoluene (BHT) was used as a positive control at a concentration of 2 g/L to compare the antioxidant effects of the plant extracts. The treated fish was subjected to smoking or sun drying and the fatty acid composition of the fish lipid extract was assessed. The results showed that the total polyphenolic, flavonoid, and tannin contents varied significantly from one plant extract to the other (p < .05). The radical scavenging and FRAP increased significantly with the concentration of the plant extracts (p < .05). An HPLC analysis of the extracts led to the preliminary identification of four hydroxycinnamic acids in M. oleifera and X. aethiopica, one anthocyanin and one flavone glycoside in M. oleifera, and four flavan-3-ols in X. aethiopica. Moreover, eight flavonols were preliminarily identified in the three plants. Compared to the control product, these plant extracts significantly protected fish PUFAs from oxidation (p < .05). The aqueous extract of A. cepa at 40 g/L better preserved omega-3 in fish during smoking and sun drying than the control product. Incorporating the three plant extracts during smoking and sun-drying processes can effectively preserve the PUFAs in fish. Therefore, these plants are viable sources of natural antioxidants in the preservation of fish products.

GC-MS-based metabolomics, antibacterial and anti-inflammatory investigations to characterize the quality of essential oil obtained from dried Xylopia aethiopica fruits from Ghana and Nigeria.

OBJECTIVES: This study sought to determine the quality of essential oil from Xylopia aethiopica fruits of different geographical origins using GC-MS-based metabolomics, bacterial quorum sensing and anti-inflammation assessment. METHODS: Essential oil was obtained from eight batches of X. aethiopica fruits from Ghana and Nigeria by hydrodistillation, characterized using gas chromatography-mass spectrometry and differences therein found using metabolomics. The respective antibacterial activity of the oils was tested against four bacterial strains: two Gram-positive strains, Staphylococcus aureus (ATCC 25923) and Bacillus licheniformis (ATCC12759), and two Gram-negative strains, Escherichia coli (ATCC25922) and Klebsiella pneumoniae (ATCC 13883). Anti-inflammation was tested using RAW 264.7 macrophage cells. KEY FINDINGS: The outcome of the study revealed that the oil of the Ghana-sourced samples exhibited superior antibacterial, cytotoxic and anti-inflammatory effects than those from Nigeria. This could be attributed to the higher levels of the bioactive compounds present in those samples. This distinction between the samples from the two countries was clearly established using the metabolomics approach, and 14 differential metabolites were found to be potential chemical markers. CONCLUSIONS: The study lends credence to the traditional uses of the essential oil of X. aethiopica as an antimicrobial and anti-inflammatory agent.