Phytochemical Analysis and Potential Biological Activities of Essential Oil from Rice Leaf

Abstract

Although many investigations on phytochemicals in rice plant parts and root exudates have been conducted, information on the chemical profile of essential oil (EO) and potent biological activities has been limited. In this study, chemical compositions of rice leaf EO and in vitro biological activities were investigated. From 1.5 kg of fresh rice leaves, an amount of 20 mg EO was obtained by distillation and analyzed by gas chromatography-mass spectrometry (GC-MS), electrospray ionization (ESI), and atmospheric pressure chemical ionization (APCI) to reveal the presence of twelve volatile constituents, of which methyl ricinoleate (27.86%) was the principal compound, followed by palmitic acid (17.34%), and linolenic acid (11.16%), while 2-pentadecanone was the least (2.13%). Two phytoalexin momilactones A and B were first time identified in EO using ultra-performance liquid chromatography coupled with electrospray mass spectrometry (UPLC/ESI-MS) (9.80 and 4.93 ng/g fresh weight, respectively), which accounted for 7.35% and 3.70% of the EO, respectively. The assays of DPPH (IC50 = 73.1 µg/mL), ABTS (IC50 = 198.3 µg/mL), FRAP (IC50 = 700.8 µg/mL) and β-carotene oxidation (LPI = 79%) revealed that EO possessed an excellent antioxidant activity. The xanthine oxidase assay indicated that the anti-hyperuricemia potential was in a moderate level (IC50 = 526 µg/mL) as compared with the standard allopurinol. The EO exerted potent inhibition on growth of Raphanus sativus, Lactuca sativa, and two noxious weeds Echinochloa crus-galli, and Bidens pilosa, but in contrast, the growth of rice seedlings was promoted. Among the examined plants, the growth of the E. crus-galli root was the most inhibited, proposing that constituents found in EO may have potential for the control of the problematic paddy weed E. crus-galli. It was found that the EO of rice leaves contained rich phytochemicals, which were potent in antioxidants and gout treatment, as well as weed management. Findings of this study highlighted the potential value of rice leaves, which may provide extra benefits for rice farmers.

Biological activities of essential oil extracted from leaves of Atalantia sessiflora Guillauminin Vietnam

“…Studies have shown that essential oils include a large content of antioxidants donating hydrogen in oxidative reactions, especially in the presence of light. Essential oils were also recognized to exhibit antifungal and antibacterial properties hence preventing plants from possible pathogenic triggers [26][27][28]. Upon biotic/abiotic stress conditions, essential oils can release their chemical substituents through a range of molecular interactions [29] and each of them exhibits different mechanisms of actions on microorganism [30].…”

Phytochemical composition analysis and evaluation of in vitro medicinal properties and cytotoxicity of five wild weeds: A comparative study

“…The β-carotene bleaching test antioxidant activity (lipid peroxidation) of the aqueous and 70% ethanolic extracts was done by the method of Minh et al . with modifications 42 . In brief, β-carotene (2 mg) (HiMedia, India) was dissolved in 10 ml of chloroform (Merck, India) and then 1 ml of the chloroform solution was added to 20 μl of linoleic acid (HiMedia-GRM10250, India) and 200 mg of Tween-80 (HiMedia-PCT1513, India).…”

“…A t and A tt are the absorbance measured after the incubation of 180 min for sample and control, respectively. Higher LPI value indicates the higher antioxidant activity 42 , 43 .…”

Antioxidant, Xanthine Oxidase, α-Amylase and α-Glucosidase Inhibitory Activities of Bioactive Compounds from Rumex crispus L. Root

“…ESI-MS analysis was conducted on negative/positive ion mode [42]. APCI-MS analysis was implemented using a mass spectrometer with an electrospray ion source [43].…”