Rice (Oryza sativa L.) is one of the main staple crops widely cultivated in the Mekong Delta. Currently, rice cultivation mainly focuses on harvesting grains or using biomass for animal feed, while the use of rice leaves as a source of bioactive compounds is still very limited. However, several studies have shown that young rice leaves contain valuable bioactive compounds such as polyphenols and chlorophyll, which possess antibacterial, antifungal, digestive-supporting, and immune-boosting properties. Therefore, young rice leaves can be considered a potential raw material for functional food products.

Polyphenols and chlorophyll are plant-based chemical components that have attracted significant health-related interest in recent decades. An increasing number of studies have demonstrated that using these plant-derived compounds has positive effects on health by regulating metabolism, body weight, chronic diseases, and promoting cell proliferation. Animal, human, and epidemiological studies have indicated that polyphenols and chlorophyll have antioxidant and anti-inflammatory properties, making them effective in preventing and treating cardiovascular diseases, neurodegenerative disorders, cancer, and obesity. In addition to their antioxidant capacity, plant extracts containing chlorophyll and polyphenols also exhibit antibacterial properties against pathogenic microbes.

The presence of plant-derived chemical compounds can offer dual benefits of antioxidant and antibacterial activities. Hence, identifying the characteristics and chemical composition of plants is essential. Several analytical techniques such as Gas Chromatography–Mass Spectrometry (GC-MS), Nuclear Magnetic Resonance (NMR), and Liquid Chromatography–Mass Spectrometry (LC-MS) are used to quantify and identify plant-derived compounds. Among these, GC-MS is considered one of the most reliable and widely used analytical platforms due to its high sensitivity. Currently, research on the chemical composition of young rice leaf powder remains limited. Therefore, analyzing these components provides a foundation for further studies on the bioactivity and potential applications of young rice leaf extracts.

Supplementing food with naturally health-enhancing components can help consumers prevent diet-related diseases, as these contain high concentrations of bioactive compounds, such as secondary plant metabolites. These compounds play a crucial role in promoting overall health. Therefore, exploring and identifying the bioactive compounds in young rice leaf powder for use as additives in functional foods and other health-promoting products presents a promising area of research that adds value to rice crops.

The young leaf powder of the Huyet Rong rice variety was analyzed for total polyphenol, total flavonoid, and total chlorophyll content. Its antioxidant capacity was determined using iron-reducing power (RP), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity assays. The antibacterial activity was tested using the agar well diffusion method against pathogenic bacteria Staphylococcus aureus and Escherichia coli. The chemical components in the rice leaf powder were identified using GC-MS analysis.

The results showed that the young rice leaf powder contained significant amounts of plant-based compounds, including polyphenols (3.15 ± 0.43 mg GAE/g), flavonoids (0.86 ± 0.03 mg QE/g), and chlorophyll (1.29 ± 0.11 mg/g). Antioxidant activity determined by DPPH, ABTS, and RP assays yielded IC50 values of 344.52 ± 5.22 µg/mL, 789.63 ± 7.56 µg/mL, and 493.25 ± 5.96 µg/mL, respectively.

The antibacterial testing showed that young rice leaf powder exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli. It showed stronger activity against the Gram-positive S. aureus, with an inhibition zone diameter of 13.67 mm, while activity against the Gram-negative E. coli was weaker, with an inhibition zone diameter of 9.45 mm.

GC-MS analysis identified 17 different bioactive compounds in the young rice leaf powder. The main chemical compounds were 1,2-Benzenedicarboxylic acid, diisooctyl ester (91.75%), phytol (2.25%), and stigmasterol (1.29%). These compounds possess various biological functions and health-enhancing benefits, making them suitable for pharmaceutical and functional food applications.

In conclusion, young rice leaf powder is a valuable source of plant-based chemical compounds and can be applied as an additive in functional food products.