Anatomical structure, flavonoid content, and antioxidant activity of Rhodomyrtus tomentosa leaves and fruits on different age and maturity level

Abstract

Abstract. Kuntorini EM, Nugroho LH, Maryani, Nuringtyas TR. 2019. Anatomical structure, flavonoid content, and antioxidant activity of Rhodomyrtus tomentosa leaves and fruits on different age and maturity level. Biodiversitas 20: 3619-3625. Karamunting (Rhodomyrtus tomentosa (Aiton.) Hassk.) is a native plant to southeast Asian countries, and is a well-known medicinal plant used to treat colic diarrhea, wounds, heartburn, abscesses, gynecopathy, and as a pain killer. However, the use of R. tomentosa has not been optimized. This research aimed to observe the anatomical structure, the location, and distribution of flavonoid and to find out the antioxidant activity based on the leaves age and the fruit maturity. Anatomical slides preparation of leaves and fruits were made using the paraffin embedding method with safranin staining. The distribution of flavonoid was analyzed by histochemical test and antioxidant activity was done with DPPH (1,1-diphenyl-2-picrylhydrazyl) method. Leaf anatomical structure shows that the leaf bifacial (dorsiventral) consisted of upper epidermis, mesophyll (palisade and sponge), collateral vascular bundle, parenchyma midrib, abaxial epidermis, globular oil cavity, and non-glandular trichome. Transverse section of green fruit consists of exocarp (thin outer layer), mesocarp (thick inner layer, soft and runny) and endocarp (thin false septa) layers. The histochemical test showed that flavonoid was observed in the leaf epidermis, mesophyll, vascular bundles, secretory cavity, parenchyma and in all fruit types exocarp, mesocarp, endocarp. Antioxidant activity showed that the extract of the young leaves (IC50 = 14.67 ppm) was stronger than the old leaves (IC50 = 19.86 ppm). The antioxidant activity of the purple fruits extract (IC50 = 12.98 ppm) was stronger than the red fruits (IC50 = 28.63 ppm) and the green fruits (IC50 = 48.36 ppm) but it was weaker than quercetin (IC50 = 1.29 ppm). The purple fruit had the highest antioxidant activity compared to other extracts. This information will be useful for developing karamunting as a potential resource of natural antioxidants for functional foods and health products.

Dietary Phenolic Compounds—Wellbeing and Perspective Applications

“…The phenylpropanoid pathway is mainly responsible for the biosynthesis of flavonoids [37]. Most flavonoids are found in leaves, flowers, fruits, and seedlings [38]. They are known for their cell-signaling, anti-thrombogenic, and neuroprotective properties [28,29].…”

Antioxidant activity and inhibition of α-glucosidase from extract and fraction of leaves and stems of Vernonia amygdalina

“…Therefore, the increase in the production of phenolic acids may be attributed to the increased activity of the PAL enzyme [30], [31]. The higher content of flavonoids and phenolics in leaves compared to stems is due to the higher amount of epidermal tissue, mesophyll, parenchyma, and secretory glands (which are storage places for secondary metabolites) present in the leaves, in contrast to the stems that mainly consist of transport tissues such as xylem and phloem [32]. Furthermore, environmental conditions such as CO2 levels, temperature [33], plant origin, age, environmental conditions of the growing place [34], and the maturity level of the plant [35].…”

Genomic analysis based on chromosome-level genome assembly reveals Myrtaceae evolution and terpene biosynthesis of rose myrtle

“…At present, many volatile compounds have been detected in rose myrtle [ 13 ], especially the leaves are enriched with (+)-α-pinene and β-caryophyllene [ 14 , 15 ]. These simple and polymeric terpenoids function as photoprotectants, antifeedants, or physical barriers, playing vital roles in plant growth, development, and environmental interaction [ 16 – 18 ]. Commercially used essential oils, including myrtle oil, lavender oil and tea tree oil, are a mixture of volatile terpenes [ 19 ], with a growing amount of importance in industrial applications [ 20 , 21 ].…”