BACKGROUND: Tomato is one of the widely cultivated crops worldwide that is affected by several pests, such as fungi (Fusarium oxysoporum, Alternaria solani), bacteria (Pectobacterium carotovorum) and weeds (Cyperus iria L., Amaranthus spinosus).A growing interest has emerged for developing plant-derived pesticidal compounds to counteract these pests. One attractive alternative is to use barnyard grass (Echinochloa crus-galli), known to be widely resistant to synthetic herbicides, as a potential biopesticide compound source.RESULTS: Phytochemical screening of the crude extract showed that phenolic compounds were the most abundant component present in barnyard grass. The crude extract was evaluated for antifungal, antibacterial and herbicidal activities. Bioassays showed inhibition against F. oxysporum (10.73 ± 1.30%) and A. solani (20.47 ± 3.51%), the causative agent of Fusarium rot and early blight disease in tomato, respectively. Antibacterial activity against P. carotovorum gave a mean zone of inhibition (paper disc diffusion assay) of 17.00 ± 1.00 mm and an IC 50 (dose-response assay) of 2.26 mg mL −1 was observed. Doseresponsive herbicidal activity on the lettuce seed germination bioassay produced an IC 50 of 459.30 ppm. Selectivity studies showed inhibition towards C. iria and A. spinosus with no effect on tomato. Lastly, bioassay-guided fractionation coupled with untargeted metabolomics studies using ultra-performance liquid chromatography with diode array detection-tandem mass spectrometry mass analyses revealed loliolide and tricin as the putative metabolites present in barnyard grass. CONCLUSION: To date, this is the first reported study on using barnyard grass as a potential alternative biopesticide against tomato pests such as fungi, bacteria and weeds.

BACKGROUND: Ludwigia hyssopifolia (G. Don) Exell, one of the problem weeds in some rice-producing countries, was studied to determine its allelopathic potential based on the effects of aqueous extracts of its tissues (leaves, roots and stem) on seedling growth of selected weeds and rice. The major phenolic compound of its leaves was also isolated and characterized. RESULTS: L. hyssopifolia aqueous leaf extract showed significant inhibition of shoot growth and biomass accumulation of weeds (Amaranthus spinosus L., Dactyloctenium aegyptium L., Cyperus iria L.) while maintaining less adverse effects on rice (crop) compared to other aqueous extracts of roots and stem. Phytochemical screening showed that phenols, tannins, flavonoids, terpenoids, saponins and coumarins are found in its leaf aqueous extract. The Folin-Ciocalteu method revealed that its leaves contain 26.66 ± 0.30 mg GAE g −1 leaf. The extract was then acid-hydrolyzed to liberate the phenolics (25 mg phenolics g −1 leaf). The major compound was isolated via preparative thin-layer chromatography using formic acid-ethyl acetate-n-hexane (0.05:4:6) solvent system. It had maximum UV absorption at 272 nm while its Fourier transform infrared spectrum revealed phenol, carboxylic acid and ether functionalities. This also had similar chromatographic mobility when run together with syringic acid in two-dimensional paper chromatography and thin-layer chromatography. CONCLUSIONS: L. hyssopifolia has potential allelopathic activity and its leaf aqueous extract showed the highest phytotoxic activity (P ≤ 0.05) indicating its potential as a bioherbicide. The most probable identity of the major phenolic compound is syringic acid.

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Ten readily available and underutilized plant materials in the Philippines were investigated for their oil content and composition, level and composition of unsaponifiable fraction and storage stability for possible nutraceutical and cosmeceutical applications. Based on oil extraction of each sample, the highest oil content of 25.00 ± 0.61 % was extracted from rambutan seed. Long chain fatty acids that can be used for skin-care products such as oleic, linoleic, linolenic and arachidic acids were detected in all food plant oils samples using gas chromatographic analysis. Docosahexaenoic acid (DHA), an omega-3 fatty acid that serves as the building block of human brain tissue and retina of the eye, was found in purslane oil. Multivariate discriminant analysis revealed that kernel oils of katchamita and carabao mangoes are relatively close based on their fatty acid profile. Close association was also exhibited by oils of malunggay seed and rice bran. Slow tendency to undergo hydrolytic rancidity of malunggay seed oil is indicated by its low free fatty acid value of 2.13 ± 0.13 meq/kg oil. A peroxide value of 0.95 ± 0.09 mg O 2 / kg of malunggay oil revealed that it is the most stable among the oils. These seven-month storage stability tests of the malunggay oil make it useful as ingredient in cosmetic products. Of the oils extracted, avocado kernel oil showed the highest unsaponifiable content (72.63 ± 2.91%). The unsaponifiable fraction was subjected to TLC analysis using 5:1 v/v petroleum ether-ethyl acetate as solvent, coupled with densitometric analysis using the CP ATLAS v. 2.0 program and results showed that the highest phytosterol content of 57.59 ± 2.80 % was found in the carabao mango seed oil. Antitumor, cholesterol-lowering, antioxidant, anti-inflammatory and antibacterial properties are the reported bioactivities of phytosterols. This study demonstrates potential sources of nutritional lipids, which can serve as functional and innovative ingredients utilized for nutraceutical and cosmeceutical applications.