Novel phenolic glucoside, origanoside, protects against oxidative damage and modulates antioxidant enzyme activity

Antioxidant, insecticidal, antifeedant, and repellent activities of oregano (Origanum vulgare)

This study aimed to assess the antioxidant capacity, the insecticidal, feeding deterrence, repellent effects against Tribolium confusum of the essential oil (EO) and the organic extracts (ME) of Origanum vulgare. The chemical composition of the EO revealed the presence thirty-nine components dominated by carvacrol (81%). With respect to the EO, the ME acted as a potent free radical scavenger with IC50 values of 0.127 and 0.058 mg/mL, respectively. The EO exhibited the most significant toxicity compared to the ME with a mortality of 62 and 20% at 0.08 µL/insect after 24h whereas the EO expressed the highest repellency compared to the ME with a PR of 70 and 38% after 24h. As for feeding deterrence, both samples influenced all nutritional indexes. The findings found in this work might help in the promotion of oregano as natural antioxidant, antifeedant, repellent and insecticide as an alternative to conventional harmful ones.

Natural diversity in phenolic components and antioxidant properties of oregano (Origanum vulgare L.) accessions, grown under the same conditions

Oregano (Origanum vulgare L.) is a rich source of biologically active components such as phenolic compounds. Here, seven pot grown O. vulgare accessions belonging to three subspecies (subsp. virens, subsp. vulgare and subsp. gracile) were investigated for their content in sixteen bioactive phenolic compounds as well as their antioxidant capacities (DPPH^• and FRAP tests), total phenolic content (TPC) and total flavonoid content (TFC) in order to identify the most suitable ones on an industrial level. HPLC analyses showed that rosmarinic acid (659.6-1646.9 mg/100 g DW) was by far the most abundant constituent, followed by luteolin (46.5-345.4 mg/100 g DW), chicoric acid (36.3-212.5 mg/100 g DW), coumarin (65.7-193.9 mg/100 g DW) and quercetin (10.6-106.1 mg/100 g DW), with variability in concentration depending on the accession and subspecies. The highest level of rosmarinic acid and TPC was obtained from Ardabil accession (subsp. virens). There was a significant and positive correlation between rosmarinic acid and antioxidant activity (r = 0.46). TFC significantly correlated to TPC (r = 0.57) as well as to chicoric acid (r = 0.73). Cluster (CA) and principal component (PCA) analyses classified the investigated accessions in three different groups. Such natural variabilities in phenolics provide the possibility of using elite plants for nutraceutical and pharmaceutical industries and domestication of highly antioxidative accessions of oregano.

Protective Effects of Mogroside V on Oxidative Stress Induced by H2O2 in Skin Fibroblasts

Purpose

Damage caused by oxidative stress leads to the premature aging of cells. Mogrosides, the main active components of Siraitia grosvenorii, have strong antioxidant activity; however, it is unclear whether mogroside V (MV) exerts these effects in skin cells. This was investigated in the present study by evaluating the protective effects of MV against oxidative damage induced by hydrogen peroxide (H₂O₂) in skin fibroblasts.

Methods

Mouse skin fibroblasts (MSFs) were treated with H₂O₂ and cell viability, total antioxidant capacity, reactive oxygen species (ROS) production, malondialdehyde (MDA) content, and antioxidant enzyme activity were assessed.

Results

Treatment with MV reduced the ROS level and MDA content in MSFs treated with H₂O₂. This was accompanied by increased superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities.

Conclusion

MV reduces H₂O₂-induced oxidative stress and enhances endogenous antioxidant activity in skin fibroblasts. Thus, MV can potentially be used as an ingredient in anti-aging cosmetic products.

Antioxidant Activity and Acteoside Analysis of Abeliophyllum distichum

This study determined acteoside and its content in Abeliophyllum distichum via HPLC/UV and LC/ESI-MS to obtain insights into the potential use of this plant as an antioxidant agent. Moreover, 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl (^•OH), and O₂^- radical scavenging activity assays were performed to assess in vitro antioxidative activity. The DPPH, ^•OH, and O₂^- radical scavenging activities of A. distichum leaf EtOH extracts at a 250 μg/mL concentration were 88.32%, 94.48%, and 14.36%, respectively, whereas those of stem extracts at the same concentration were 88.15%, 88.99%, and 15.36%, respectively. The contents of acteoside in A. distichum leaves and stems were 162.11 and 29.68 mg/g, respectively. Acteoside was identified as the main antioxidant compound in A. distichum leaves, which resulted in DPPH, ^•OH, and O₂^- radical scavenging activities of 82.84%, 89.46%, and 30.31%, respectively, at a 25 μg/mL concentration. These results indicate that A. distichum leaves and stems containing the antioxidant acteoside can be used as natural ingredients for functional and nutritional supplements.

Effect of prolonged water stress on essential oil content, compositions and gene expression patterns of mono- and sesquiterpene synthesis in two oregano (Origanum vulgare L.) subspecies

Origanum vulgare L., recognized throughout the world as a popular medicinal and flavoring herb, contains a wide array of medicinally active components, including phenolic glucosides, flavonoids, tannins, sterols and high amounts of terpenoids. Especially the latter are often extracted by hydrodistillation resulting in the so-called essential oil that is rich in monoterpenes (e.g. carvacrol, thymol, linalyl acetate) and/or sesquiterpenes (e.g. (E)-β-caryophyllene, germacrene D, bicyclogermacrene, β-caryophyllene oxide). Water stresses in the arid and semiarid regions of the world severely affect growth and productivity of oregano. To determine the variation in essential oil and gene expression pathway of Iranian oregano under prolonged water stress, two native subspecies of O. vulgare (subsp. virens and subsp. gracile) were studied. The plants, grown in pots, were subjected to three water stress conditions, i.e. no stress, mild stress (60± 5% FMC) and moderate stress (40± 5% FMC). The studied subspecies exhibited significant differences in essential oil content, compositions, and patterns of gene expression under water stress conditions. The essential oil of O. vulgare subsp. gracile was rich in the phenolic monoterpene carvacrol (46.86-52.07%), whereas the sesquiterpene hydrocarbon (Z)-α-bisabolene (39.17-42.64%) was the major constituent in the oil of O. vulgare subsp. virens. Both the mild and moderate water stresses significantly increased the essential oil content of O. vulgare subsp. gracile, but did not significantly change the essential oil content of O. vulgare subsp. virens nor the level of carvacrol and (Z)-α-bisabolene in the investigated subspecies. Interestingly, the amount of (E)-β-caryophyllene in O. vulgare subsp. virens was significantly increased under water stress conditions. Gene expression studies supported the above findings and demonstrated that there are two different pathways affecting the biosynthesis of the terpenoid precursors geranyl pyrophosphate (GPP) and farnesyl pyrophosphate (FPP). In O. vulgare subsp. gracile, HMGR, Ovtps2 and CYP71D180 transcript were up-regulated under mild and moderate water stress conditions. Transcription of FPPS was apparently down-regulated in water-stressed O. vulgare subsp. gracile. Investigation of terpene synthases expression levels in oregano subspecies demonstrated that Ovtps2 and Ovtps6 controlled the concentration of carvacrol and (E)-β-caryophyllene in oregano essential oils, respectively.

Antioxidant, anti-adipocyte differentiation, antitumor activity and anthelmintic activities against Anisakis simplex and Hymenolepis nana of yakuchinone A from Alpinia oxyphylla

Background

Alpinia oxyphylla is a common remedy in traditional Chinese medicine. Yakuchinone A is a major constituent of A. oxyphylla and exhibits anti-inflammatory, antitumor, antibacterial, and gastric protective activities.

Methods

Antioxidant and antitumor characteristics of yakuchinone A in skin cancer cells as well as novel mechanisms for the inhibition of adipocyte differentiation, cestocidal activities against Hymenolepis nana adults, and nematocidal activities against Anisakis simplex larvae are investigated.

Results

Yakuchinone A presents the ability of the removal of DPPH·and ABTS⁺ free radicals and inhibition of lipid peroxidation. Yakuchinone A suppresses intracellular lipid accumulation during adipocyte differentiation in 3 T3-L1 cells and the expressions of leptin and peroxisome proliferator-activated receptor γ (PPARγ). Yakuchinone A induces apoptosis and inhibits cell proliferation in skin cancer cells. The inhibition of cell growth by yakuchinone A is more significant for non-melanoma skin cancer (NMSC) cells than for melanoma (A375 and B16) and noncancerous (HaCaT and BNLCL2) cells. Treatment BCC cells with yakuchinone A shows down-regulation of Bcl-2, up-regulation of Bax, and an increase in cleavage poly (ADP-ribose) polymerase (PARP). This suggests that yakuchinone A induces BCC cells apoptosis through the Bcl-2-mediated signaling pathway. The anthelmintic activities of yakuchinone A for A. simplex are better than for H. nana.

Conclusions

In this work, yakuchinone A exhibits antioxidative properties, anti-adipocyte differentiation, antitumor activity, and anthelmintic activities against A. simplex and H. nana.