Bioactive Compounds and Antioxidant Efficacy of Djulis (Chenopodium formosanum) Leaves: Implications for Sustainable Cosmeceutical Development

Abstract

Chenopodium formosanum (djulis), well known for its vivid color variation during diverse senescence stages, has attracted attention for its perceived health benefits and antioxidant capacity. Djulis leaves, often discarded as biowaste after harvesting, were evaluated for their potential as a source of antioxidant compounds. The current study analyzes the physicochemical and antioxidant activities of red, green, and yellow djulis leaf extracts across various senescence stages to probe their prospective utility in cosmeceuticals. Various plant compounds including total carbohydrates, phenolics and flavonoids, chlorophyll a and b, and betaxanthins and betacyanins were measured using spectrophotometric techniques. Antioxidant potential was assessed using DPPH, FRAP, CUPRAC, TEAC, and DMPD assays. Green djulis leaves displayed elevated total carbohydrate and chlorophyll levels, whereas red djulis leaves exhibited heightened phenolic, flavonoid, betaxanthin, and betacyanin content, indicating its suitability for cosmeceutical applications. Antioxidant evaluations revealed substantial disparities among the extracts, with red djulis leaf extract demonstrating superior antioxidant activity in most assays. These findings revealed the distinct antioxidant profiles of djulis leaf extracts influenced by color and senescence stage. These findings advance our understanding of the bioactive attributes of djulis leaves and their potential for incorporation into functional products.

Keywords: Chenopodium formosanum; antioxidant; cosmeceuticals; djulis leaves.

Figure 1

(A) Djulis (Chenopodium formosanum). (B) Green djulis leaf. (C) Red djulis leaf. (D) Yellow djulis leaf.

Figure 2

Bioactive compound content of djulis leaves at different senescence stages. (A) Total carbohydrate content (mg glucose/g DW), where ‘mg/g DW’ represents milligrams of carbohydrate per gram of dry weight. (B) Total phenolic content (mg gallic acid/g DW), quantified as milligrams of gallic acid equivalents per gram of dry weight. (C) Total flavonoid content (mg quercetin/g DW), expressed as milligrams of quercetin equivalents per gram of dry weight. (D) Chlorophyll a content (mg/g DW). (E) Chlorophyll b content (mg/g DW). (F) Betaxanthin content (μg/g DW). (G) Betacyanin content (μg/g DW). The results highlight significant differences in the bioactive profiles of green, red, and yellow djulis leaves. Error bars represent standard deviations (n = 3). Means with different letters indicate statistically significant differences at p < 0.05 based on Duncan’s multiple range test.

Figure 3

Antioxidant activities of djulis leaf extracts at different senescence stages measured by various in vitro assays: (A) DPPH radical scavenging activity (%, w/v), expressed as the percentage of free radical scavenging relative to the standard (gallic acid). (B) Ferric-reducing antioxidant power (FRAP), expressed in mg FeSO₄ equivalents per gram of dry weight (mg FeSO₄/g DW). (C) Cupric-reducing antioxidant power (CUPRAC), expressed in mg ascorbic acid equivalents per gram of dry weight (mg ascorbic acid/g DW). (D) Trolox equivalent antioxidant capacity (TEAC), expressed as a percentage of antioxidant capacity compared to the Trolox standard. (E) DMPD antioxidant capacity, expressed in mg ferric chloride equivalents per gram of dry weight (mg FeCl₃/g DW). These units provide a standardized measure of antioxidant activity, enabling comparisons across different assays and extracts. Error bars represent standard deviations (n = 3). Means with different letters indicate statistically significant differences at p < 0.05 based on Duncan’s multiple range test.

Figure 4

(A) L*, (B) a*, and (C) b* values representing the color parameters of djulis leaf gels, and (D) visual appearance of the gels prepared from different djulis leaf extracts. Abbreviations: B refers to the blank control gel (no djulis extract added); G-1, G-2, and G-3 refer to gels prepared from green djulis leaf extracts at three different concentrations; R-1, R-2, and R-3 refer to gels prepared from red djulis leaf extracts at three different concentrations; Y-1, Y-2, and Y-3 refer to gels prepared from yellow djulis leaf extracts at three different concentrations. Error bars represent standard deviations (n = 3).

Figure 5

Dermatological analysis of djulis leaf gel formulations over 20 min, showing changes in (A) moisture level, (B) oil level, (C) texture level, (D) complexion level, and (E) 3D level. Abbreviations: B refers to the blank control gel (no djulis extract added); G-1, G-2, and G-3 represent gels prepared from green djulis leaf extracts at three different concentrations; R-1, R-2, and R-3 represent gels prepared from red djulis leaf extracts at three different concentrations; Y-1, Y-2, and Y-3 represent gels prepared from yellow djulis leaf extracts at three different concentrations. Error bars represent standard deviations (n = 3).

Figure 6

Correlation map showing the relationships between total carbohydrate (TC), total phenolic content (TPC), total flavonoid content (TF), chlorophyll a, chlorophyll b, betaxanthin, betacyanin, and antioxidant activities (DPPH, FRAP, CUPRAC, TEAC, and DMPD). Box colors represent the correlation coefficients: blue shades indicate negative correlations (darker blue = stronger negative correlation), red shades indicate positive correlations (darker red = stronger positive correlation), and white indicates no significant correlation.