Induction of Apoptosis by β-Carotene and Dimethyl Tetrasulfide Assisted by UVA Irradiation in HL-60 Cells

Bioefficacy of the ethanolic crude extract of the wild leek, Allium ampeloprasum L. (Amaryllidaceae), against the third and fourth larval stages of Aedes aegypti L. (Culicidae)

Insecticide resistance is a threat to vector control worldwide. In the Philippines, dengue burden remains significant, thus prioritizing the need to develop eco-friendly control strategies and tools against mosquito vectors. Various Allium species have been found to possess larvicidal activity against dengue-carrying mosquitoes. In this study, the larvicidal activity of the crude extract of Allium ampeloprasum L. (Asparagales: Amaryllidaceae) was studied in concentrations ranging from 1 to 10,000 mg/L against the third (L3) and fourth (L4) larval instars of Aedes aegypti L. Larval mortality at 48 h were subjected to probit analysis and Kruskal-Wallis H test to estimate lethal concentrations and to determine significant means among the groups, respectively. Results show that the crude extract of A. ampeloprasum L. demonstrated larvicidal activity against the L3 and L4 Ae. aegypti L. Concentrations corresponding to 50% mortality (Lethal Concentration 50 [LC50]) among L3 and L4 larvae were estimated at 2,829.16 and 13,014.06 mg/L, respectively. Moreover, 90% mortality (LC90) in the L3 and L4 larvae were estimated at 9,749.75 and 57,836.58 mg/L, respectively. Only 1,000 and 10,000 mg/L for L3, and the 10,000 mg/L for L4, had comparable larvicidal action to the commercial larvicide used as a positive control. The results support the presence of bioactive compounds with larvicidal properties, thus suggesting A. ampeloprasum L. as a potential source of active ingredients for the development of a plant-based larvicide.

Influence of Oxygen-Containing Sulfur Flavor Molecules on the Stability of β-Carotene under UVA Irradiation

The influence of 11 kinds of oxygen-containing sulfur flavor molecules was examined on β-carotene stability under UVA irradiation in ethanol system. Both the effects of sulfides on dynamic degradation of β-carotene and the relation between structure and effect were investigated. The oxidation products of β-carotene accelerated by sulfides under UVA irradiation were also identified. The results indicated that the disulfides had more obvious accelerative effects on the photodegradation of β-carotene than mono sulfides. The degradation of β-carotene after methyl (2-methyl-3-furyl) disulfide (MMFDS), methyl furfuryl disulfide (MFDS) and bis(2-methyl-3-furyl) disulfide (BMFDS) exposure followed first-order kinetics. Furan-containing sulfides such as MMFDS and BMFDS showed more pronounced accelerative effects than their corresponding isomers. The oxidation products were identified as 13-cis-β-carotene, 9,13-di-cis-β-carotene and all-trans-5,6-epoxy-β-carotene. These results suggest that both the sulfur atom numbers and the furan group in oxygen-containing sulfides play a critical role in the photooxidation of β-carotene.

Direct assessments of the antioxidant effects of the novel collagen peptide on reactive oxygen species using electron spin resonance spectroscopy

In the present study, we evaluated the antioxidant effects of a pepsin-treated novel collagen peptide (P-NCP) on reactive oxygen species (ROS) such as hydroxyl radical (HO(•)), superoxide anion radical (O(2)(•-)), and singlet oxygen ((1)O(2)), and the effects on cell viability after ultraviolet ray (UV) irradiation of human fibroblasts. We confirmed, using electron spin resonance, that P-NCP directly inhibited HO(•) and (1)O(2). Furthermore, addition of P-NCP to fibroblasts inhibited cell death induced by UVA (400-315 nm) irradiation in a dose-dependent manner. In addition, the antioxidant effect on (1)O(2) was observed in the peptide fractions rich in Gly, Pro, Hyp, Glu, Ala, and Arg. We found that Gly, Hyp, Glu, and Ala directly scavenged (1)O(2). These results indicated that a peptide sequence including Gly, Hyp, Glu, and Ala could play a key role in the antioxidant effects of P-NCP on (1)O(2). It was suggested that P-NCP can inhibit photo-aging related to ROS owing to its antioxidant effects.