Changes in Phytochemical Synthesis, Chalcone Synthase Activity and Pharmaceutical Qualities of Sabah Snake Grass (Clinacanthus nutans L.) in Relation to Plant Age

Abstract

In the current study, changes in secondary metabolite synthesis and the pharmaceutical quality of sabah snake grass leaves and buds were considered in relation to plant age (1 month, 6 months, and 1 year old). The activity of the enzyme chalcone synthase (CHS, EC 2.3.1.74) was measured, as it is a key enzyme for flavonoid production. Significant differences in total flavonoid (TF) production were observed between the three plant growth periods and the different plant parts. The highest contents of TF (6.32 mg/g dry weight [DW]) and total phenolic (TP) (18.21 mg/g DW) were recorded in 6-month-old buds. Among the flavonoids isolated in this study the most important ones based on concentration were from high to low as follows: catechin > quercetin > kaempferol > luteolin. Production of phenolic acids increased from 1 to 6 months, but after 6 months up to 1 year of age, they decreased significantly. The highest contents of caffeic acid (0.307 mg/g DW) and gallic acid (5.96 mg/g DW) were recorded in 1-year and 6-month-old buds, respectively. The lowest and highest activity of CHS was recorded in 1-month and 6-month-old buds with values of 3.6 and 9.5 nkat/mg protein, respectively. These results indicate that the increment in flavonoids and phenolic acids in 6-month-old buds can be attributed to an increase in CHS activity. The highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) activity was observed in the extract of 1-year-old buds followed by 6-month-old buds, with 50% of free radical scavenging (IC50) values of 64.6 and 73.5 µg/mL, respectively. Interestingly, a ferric reducing OPEN ACCESSMolecules 2014, 19 17633 antioxidant power (FRAP) assay showed a higher activity in 6-month-old buds (488 μM of Fe(II)/g) than in 1-year-old buds (453 μM of Fe(II)/g), in contrast to the DPPH result. Significant correlations (p < 0.05) were observed between CHS enzyme activity and FRAP activity, TF, catechin, and kaempferol content. Extracts of 6-month-old bud exhibited a significant in vitro anticancer activity against HeLa cancer cells with IC50 value of 56.8 µg/mL. These results indicate that early harvesting of snake grass (6-month-old) may yield increased concentrations of secondary metabolites, which are potent antioxidant compounds.

Changes in phytochemical contents in different parts of Clinacanthus nutans (Burm. f.) lindau due to storage duration

“…Furthermore, the highest initial flavonoid content is attributed to young leaves, followed by young stems. Ghasemzadeh et al (2014) also confirmed that phenolic contet of C. nutans was higher in early growth stage compared with matured stages. But, these findings are not in conformity with those of Nor Qhairul Izzreen & Mohd Fadzelly (2013), who reported that C. sinensis (green tea) contains highest total flavonoids in shoots (35 mg rutin 100 g -1 ) followed by young (32 mg rutin 100 g -1 ) and matured leaves (21 mg rutin 100 g -1 ).…”

“…Rafat et al (2009) also reported similar findings from their study with A. paniculata. Ghasemzadeh et al (2014) on the other hand, recorded higher DPPH value in 1-year -old buds than in 6-month-old buds of C. nutans.…”

Correlation of Total Phenolic, Flavonoid and Carotenoid Content of Phyllanthus emblica Extract from Bandung with DPPH Scavenging Activities

“…The environmental conditions. 5 such as sunlight condition, 10 the marurity part of plant and differences part of plant could be a factor to differences type and quantity secondary metabolites.…”

“…condition, air pressure and temperature. 10 Beside that, the maturity part of plant could be a factor to differences type and quantity secondary metabolites. 11,12 Antioxidants are one of the components needed in the body, to counteract free radicals.…”

Evaluation of Total Phenolic Compound and Cytotoxic Activity of Clinacanthus nutans

“…The ovary is packed into two cells and each cell contains two ovules [9] . Phytochemical analysis has shown that C. nutans contains several kinds of clinamide derivatives [10] , alkaloids [11] , chlorophyll [12] , flavonoids [13] , phenolic compounds [14] .…”