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Traditional Malaysian vegetables, also known as ulam, are believed to have healing properties among the local community. Ulam is commonly reported to have high antioxidant content which makes it a popular food. The purpose of this paper is to determine the teratogenic potential of eight ulam, using zebrafish model. The tested ulam were Cosmos caudatus, Gynura procumbens, Labisia pumila var. alata, Phaleria macrocarpa, Polygonum minus, Piper sarmentosum, Premna foetida and Sauropus androgynous.

Methanol extract of ulam was prepared using the maceration method. Various concentrations of extracts were tested against fish embryo short-term toxicity test. The lethal concentration (LC₅₀) and teratogenic effect of the ulam were determined.

Among all tested species, L. pumila, P. foetida and S. androgynous showed 100% lethal effect towards zebrafish embryos at concentrations of 10 µg/mL, 1,000 µg/mL and 100 µg/mL, respectively. The three ulam have exhibited teratogenic effect on zebrafish embryos after 72 h post-fertilization. L. pumila had induced yolk sac edema at 1.0 µg/mL for normalized measurement of 108.3 ± 2.0% (which is higher than negative control, p < 0.05, median = 110.7%), while P. foetida had induced pericardial edema at 100 µg/mL for normalized measurement of 124.0 ± 4.6% (which is higher than negative control, p < 0.05, median = 124.3%). On the other hand, S. androgynus induced curve trunk at 30 µg/mL for the presence of 70.9 ± 4.2%.

The teratogenic effect of L. pumila, P. foetida and S. androgynous suggests the possible disruption in the embryogenesis in zebrafish, namely Notch, vascular endothelial growth factor (VEGF) and retinoic acid pathways. The results of ulam gave possible implications and insights on the cancer pathways involved, which could be a useful target for cancer research. This is the first report on teratogenicity evaluation of Malaysian ulam showing relationship to cancer pathways by using zebrafish embryo model.

Moringa oleifera (MO) is a herbal remedy that is rich in essential amino acids and phytochemicals in the leaves, seeds and pods. It is becoming a famous food in various ethnic groups, and the consumption is increasing worldwide. However, there is no safety profile of the hydroalcoholic MO leaf extracts, or documented teratogenicity aspect. This study was sought to compare the antioxidant activity and the teratogenicity of hydroalcoholic MO leaf extracts in the zebrafish embryo.

MO leaves were extracted with aqueous alcohols (ethanol or methanol: water, 80:20 v/v) using the Soxhlet method. The antioxidant capacity was determined using DPPH assay. The concentrations of extracts ranging from 3 to 1,000 µg/mL were used to examine the toxicity and teratogenicity on the zebrafish embryo.

Both hydroalcoholic MO leaf extracts were positive for alkaloids, terpenoids, steroids, tannins, flavonoids, phenols, coumarins, quinones and glycosides, except saponins only absent in aqueous methanol extract. The antioxidant capacity based on lC₅₀, was 15.92 ± 3.62 mg/mL for aqueous methanolic and 25.28 ± 2.89 mg/mL for aqueous ethanolic extract. For acute toxicity, the aqueous methanolic extract has lower LC₅₀ (163.87 ± 12.88 µg/mL) compared to aqueous ethanolic extract (337.48 ± 30.04 µg/mL). The embryo treated with aqueous methanolic extract showed phenotypic defect but not on the aqueous ethanolic extract.

This study suggests that aqueous methanol of MO leaves extract has better antioxidant capacity compared to ethanol, and ethanolic leaf extract is safer (higher LC50 and no teratogenicity) than methanolic extract.

The purpose of this paper is to evaluate the antioxidant activity and toxicity of Clinacanthus nutans leaves from three conventional extraction methods, i.e. maceration, Soxhlet and magnetic stirring.

Total flavonoid content (TFC) and phenolic content (TPC) were determined using colorimetric method of aluminum chloride and Folin-Ciocalteu (FC) assay, respectively. Antioxidant property of C. nutans was evaluated using 2,2'-diphenyl-1-pierylhydrazyl (DPPH) free radical scavenging assay. Cytotoxic activity of C. nutans against brine shrimp was evaluated based on LC50 (lethality concentration) after 24 h exposure to the plant extract.

The highest TPC of C. nutans was observed with Soxhlet extraction method (98.87 ± 10.43 mg of gallic acid equivalents (GAE/g) followed by maceration (68.77 ± 2.45 mg of GAE/g) and magnetic stirring (46.75 ± 2.45 mg of GAE/g). Interestingly, remarkable highest TFC was observed with magnetic stirring (568.90 ± 4.85 mg of rutin equivalent (RE)/g) followed by maceration (249.60 ± 2.79 mg of RE/g) and Soxhlet (174.8 ± 1.74 mg of RE/g). On the other hands, the extract obtained using maceration method showed the highest antioxidant activity (IC50: 14.18 mg/mL compared to ascorbic acid 144.36 µg/mL). Cytotoxicity of C. nutans from all extraction methods showed similar LC50 values with maceration (3.81 mg/mL), Soxhlet (2.61 mg/mL) and magnetic stirring (4.56 mg/mL), respectively.

Both phenolic and flavonoids are responsible for the antioxidant activity, of C. nutans extracts. Based on Meyer's toxicity index, all extracts were nontoxic (LC50>1 mg/mL).