Isolation and identification of four antioxidants from Rhodiola crenulata and evaluation of their UV photoprotection capacity in vitro

Comparison of polysaccharides from stem barks and flowers of Magnolia officinalis: Compositional characterization, hypoglycemic and photoprotection activities

The extraction of polysaccharides from stem barks and flowers of Magnolia officinalis were optimized using response surface methodology and the maximum yields were 4.12 ± 0.06 % and 5.5 ± 0.08 %, respectively. Three homogeneous polysaccharides including MOBP-I, MOBP-II and MOFP-I were further purified and their compositional characterization were compared. Molecular weights of MOBP-I, MOBP-II and MOFP-I were 5.9 × 103, 6.8 × 103 and 3.9 × 104 Da, respectively. Gas chromatography (GC) analysis suggested that MOBP-I, MOBP-II and MOFP-I were composed of rhamnose, arabinose, mannose, glucose and galactose at different ratios and exhibited different appearance and glycosidic linkages. MOFP-I but not MOBP-I and MOBP-II had three helix structures. MOBP-I, MOBP-II and MOFP-I showed significant hypoglycemic and photoprotection capacities with different efficacy. MOBP-I had greater hypoglycemic activity, as evidenced by the increased α-glucosidase inhibition activity and glucose consumption in insulin-resistant HepG2 cells. MOBP-II and MOFP-I were more powerful in reversing ultraviolet-B (UVB)-irradiated photoaging of HaCaT cells. The difference of polysaccharides compositions might explain for their bioactivity discrepancy.

α-Arbutin ameliorates UVA-induced photoaging through regulation of the SIRT3/PGC-1α pathway

Owing to its tyrosinase inhibitory activity, α-arbutin has been added to several skin care products as a skin-lightening agent. However, the protective effect of α-arbutin against ultraviolet A (UVA)-induced photoaging has not been well investigated. The present study was designed to investigate the photoprotective effect and mechanism of α-arbutin against UVA-induced photoaging. In vitro experiments, HaCaT cells were treated with UVA at a dose of 3 J/cm2 to evaluate the anti-photoaging effect of α-arbutin. α-Arbutin was found to exhibit a strong antioxidant effect by increasing glutathione (GSH) level and inhibiting reactive oxygen species (ROS) production. Meanwhile, α-arbutin markedly improved the expression of sirtuin 3 (SIRT3) and peroxisome proliferator-activated receptor γ coactivator 1 α (PGC-1α) proteins, initiating downstream signaling to increase mitochondrial membrane potential and mediate mitochondrial biogenesis, and improve mitochondrial structure significantly. In vivo analysis, the mice with shaved back hair were irradiated with a cumulative UVA dose of 10 J/cm2 and a cumulative ultraviolet B (UVB) dose of 0.63 J/cm2. The animal experiments demonstrated that α-arbutin increased the expression of SIRT3 and PGC-1α proteins in the back skin of mice, thereby reducing UV-induced skin damage. In conclusion, α-arbutin protects HaCaT cells and mice from UVA damage by regulating SIRT3/PGC-1α signaling pathway.

Rapid Screening of Chemical Components in Salvia miltiorrhiza with the Potential to Inhibit Skin Inflammation

Hyaluronidase possesses the capacity to degrade high-molecular-weight hyaluronic acid into smaller fragments, subsequently initiating a cascade of inflammatory responses and activating dendritic cells. In cases of bacterial infections, substantial quantities of HAase are generated, potentially leading to severe conditions such as cellulitis. Inhibiting hyaluronidase activity may offer anti-inflammatory benefits. Salvia miltiorrhiza Bunge, a traditional Chinese medicine, has anti-inflammatory properties. However, its effects on skin inflammation are not well understood. This study screened and evaluated the active components of S. miltiorrhiza that inhibit skin inflammation, using ligand fishing, enzyme activity assays, drug combination analysis, and molecular docking. By combining magnetic nanomaterials with hyaluronidase functional groups, we immobilized hyaluronidase on magnetic nanomaterials for the first time in the literature. We then utilized an immobilized enzyme to specifically adsorb the ligand; two ligands were identified as salvianolic acid B and rosmarinic acid by HPLC analysis after desorption of the dangling ligands, to complete the rapid screening of potential anti-inflammatory active ingredients in S. miltiorrhiza roots. The median-effect equation and combination index results indicated that their synergistic inhibition of hyaluronidase at a fixed 3:2 ratio was enhanced with increasing concentrations. Kinetic studies revealed that they acted as mixed-type inhibitors of hyaluronidase. Salvianolic acid B had Ki and Kis values of 0.22 and 0.96 μM, respectively, while rosmarinic acid had values of 0.54 and 4.60 μM. Molecular docking revealed that salvianolic acid B had a higher affinity for hyaluronidase than rosmarinic acid. In addition, we observed that a 3:2 combination of SAB and RA significantly decreased the secretion of TNF-α, IL-1, and IL-6 inflammatory cytokines in UVB-irradiated HaCaT cells. These findings identify salvianolic acid B and rosmarinic acid as key components with the potential to inhibit skin inflammation, as found in S. miltiorrhiza. This research is significant for developing skin inflammation treatments. It demonstrates the effectiveness and broad applicability of the magnetic nanoparticle-based ligand fishing approach for screening enzyme inhibitors derived from herbal extracts.

The Effect of α-Arbutin on UVB-Induced Damage and Its Underlying Mechanism

Ultraviolet radiation can heighten tyrosinase activity, stimulate melanocyte production, impede the metabolism of numerous melanocytes, and result in the accumulation of plaques on the skin surface. α-Arbutin, a bioactive substance extracted from the arbutin plant, has been widely used for skin whitening. In this study, the whitening effect of α-arbutin by inhibiting tyrosinase activity and alleviating the photoaging effect induced by UVB are investigated. The results indicate that α-arbutin can inhibit skin inflammation, and its effectiveness is positively correlated with concentration. Moreover, α-arbutin can reduce the skin epidermal thickness, decrease the number of inflammatory cells, and down-regulate the expression levels of IL-1β, IL-6 and TNF-α, which are inflammatory factors. It also promotes the expression of COL-1 collagen, thus playing an important role in anti-inflammatory action. Network pharmacology, metabolomics and transcriptomics further confirm that α-arbutin is related to the L-tyrosine metabolic pathway and may interfere with various signaling pathways related to melanin and other photoaging by regulating metabolic changes. Therefore, α-arbutin has a potential inhibitory effect on UVB-induced photoaging and possesses a whitening effect as a cosmetic compound.

Semen Ziziphus jujube Saponins Protects HaCaT Cells against UV Damage and Alleviates the Aging of Caenorhabditis elegans

The role of Semen Ziziphus jujube saponins in sedative and hypnosis has attracted much attention. The study aimed to investigate its possible UV damage protection and anti-aging effects. Total saponins (SZR I) and purified saponins (SZR II) were analyzed and compared by infrared spectroscopy and high-performance liquid chromatography (HPLC). The protective effects of SZR I, SZR II, and their three monomers on HaCaT cells damaged by UV were studied, and their anti-aging activities were observed by Caenorhabditis elegans with paraquat-induced oxidative stress. The results showed that SZR I and SZR II differ in chemical composition but both have the same three monomers. The cell survival rate treated with SZR I and SZR II at a concentration of 400 μg/mL increased by 34.45 and 88.98%, respectively, indicating that they could promote the proliferation of UVB-damaged HaCaT cells. Jujuboside A, Jujuboside B, and spinosin from the saponins exhibited similar effects on UVB-damaged HaCaT cells. SZR I and SZR II had little effect on reproductive performance but could delay the senescence caused by heat and oxidative stress of the C. elegans model. These results provide useful data that Semen Z. jujube saponin is a potential natural product with UV damage protection and anti-aging characteristics.

Anti-senescence effects of Rhodiola crenulate extracts on LO2 cells and bioactive compounds

ETHNOPHARMACOLOGICAL RELEVANCE

Rhodiola crenulata (Rc) is a traditional herb, used in Tibetan medicine, has shown promise efficacy in physical performance improvement, work capacity enhancement, fatigue elimination, and altitude sickness prevention. Also, Rc exhibited therapeutic effects on aging-related diseases. However, relevant researches on Rc and their bioactive components are quite few and needs further investigation.

AIM OF THE STUDY

The objective of this study was to understand the relationship between phytochemical profiles and their activities of Rc extracts.

MATERIALS AND METHODS

Rc extracts prepared by solvents with various hydrophilicity (i.e. aqueous ethanol (70%, v/v), water, and ethyl acetate), and their chemical compositions and specific compounds were analyzed by chemical analysis method and ultra-performance liquid chromatography quadruple time-of-flight mass spectrometry (UPLC-QTOF-MS). The regulate effects of Rc extracts on senescence and antioxidant activity were evaluated using the models of LO₂ cells and Caenorhabditis elegans.

RESULTS

The 70% ethanol extracts exhibited better regulating effects on senescence via the assays of senescence -associated β-galactosidase (SAβG) staining and lifespan, which was consistent with the higher antioxidant activities observed based on the results of antioxidant assays. A total of 14 phytochemicals have been identified in 70% ethanol extracts, whereas the other two extracts contained much fewer compounds in varieties. Phytochemical profile of water extract was similar to the first half (polar compounds, running time: 0-6 min) of 70% ethanol extract profile, while those of ethyl acetate extract was consistent with its second half (more nonpolar compounds, running time: 6-12 min).

CONCLUSIONS

The 14 phytochemicals in Rc might exhibit additive or synergistic effects on senescence regulating and antioxidant activities, providing theoretical basis for daily administration of Rc.

Exploring Mycosporine-like Amino Acid UV-Absorbing Natural Products for a New Generation of Environmentally Friendly Sunscreens

Human skin needs additional protection from damaging ultraviolet radiation (UVR: 280-400 nm). Harmful UVR exposure leads to DNA damage and the development of skin cancer. Available sunscreens offer chemical protection from detrimental sun radiation to a certain extent. However, many synthetic sunscreens do not provide sufficient UVR protection due to the lack of photostability of their UV-absorbing active ingredients and/or the lack of ability to prevent the formation of free radicals, inevitably leading to skin damage. In addition, synthetic sunscreens may negatively affect human skin, causing irritation, accelerating skin aging and even resulting in allergic reactions. Beyond the potential negative effect on human health, some synthetic sunscreens have been shown to have a harmful impact on the environment. Consequently, identifying photostable, biodegradable, non-toxic, and renewable natural UV filters is imperative to address human health needs and provide a sustainable environmental solution. In nature, marine, freshwater, and terrestrial organisms are protected from harmful UVR through several important photoprotective mechanisms, including the synthesis of UV-absorbing compounds such as mycosporine-like amino acids (MAAs). Beyond MAAs, several other promising, natural UV-absorbing products could be considered for the future development of natural sunscreens. This review investigates the damaging impact of UVR on human health and the necessity of using sunscreens for UV protection, specifically UV-absorbing natural products that are more environmentally friendly than synthetic UV filters. Critical challenges and limitations related to using MAAs in sunscreen formulations are also evaluated. Furthermore, we explain how the genetic diversity of MAA biosynthetic pathways may be linked to their bioactivities and assess MAAs' potential for applications in human health.

Bibliometric Study of Adaptogens in Dermatology: Pharmacophylogeny, Phytochemistry, and Pharmacological Mechanisms

Background

Adaptogens are a class of medicinal plants that can nonspecifically enhance human resistance. Most of the plant adaptogens have relevant applications in dermatology, but there are still few studies related to their particular action and co-operative mechanisms in topical skin application.

Methods

Plant adaptogens related articles and reviews that published between 1999 and 2022 were obtained from the Web of Science Core Collection database. Various bibliographic elements were collected, including the annual number of publications, countries/regions, and keywords. CiteSpace, a scientometric software, was used to conduct bibliometric analyses. Also, the patsnap global patent database was used to analyze the patent situation of plant adaptogens in the field of cosmetics up to 2021.

Results

We found that the effects of plant adaptogens on skin diseases mainly involve atopic dermatitis, acne, allergic contact dermatitis, psoriasis, eczema, and androgenetic alopecia, etc. And the effects on skin health mainly involve anti-aging and anti-photoaging, anti-bacterial and anti-fungal, anti-inflammatory, whitening, and anti-hair loss, etc. Also, based on the results of patent analysis, it is found that the effects of plant adaptogens on skin mainly focus on aging retardation. The dermatological effects of plant adaptogens are mainly from Fabaceae Lindl., Araliaceae Juss. and Lamiaceae Martinov., and their mainly efficacy phytochemical components are terpenoids, phenolic compounds and flavonoids.

Conclusion

The plant adaptogens can repair the skin barrier and maintain skin homeostasis by regulating the skin HPA-like axis, influencing the oxidative stress pathway to inhibit inflammation, and regulating the extracellular matrix (ECM) components to maintain a dynamic equilibrium, ultimately achieving the treatment of skin diseases and the maintenance of a healthy state.

Arbutin: Occurrence in Plants, and Its Potential as an Anticancer Agent

Arbutin, a hydroquinone glucoside, has been detected in ca. 50 plant families, especially in the plants of the Asteraceae, Ericaceae, Proteaceae and Rosaceae families. It is one of the most widely used natural skin-whitening agents. In addition to its skin whitening property, arbutin possesses other therapeutically relevant biological properties, e.g., antioxidant, antimicrobial and anti-inflammatory, as well as anticancer potential. This review presents, for the first time, a comprehensive overview of the distribution of arbutin in the plant kingdom and critically appraises its therapeutic potential as an anticancer agent based on the literature published until the end of August 2022, accessed via several databases, e.g., Web of Science, Science Direct, Dictionary of Natural Products, PubMed and Google Scholar. The keywords used in the search were arbutin, cancer, anticancer, distribution and hydroquinone. Published outputs suggest that arbutin has potential anticancer properties against bladder, bone, brain, breast, cervix, colon, liver, prostate and skin cancers and a low level of acute or chronic toxicity.

Photoprotective Potential, Cytotoxicity, and UPLC-QTOF/MS Analysis on Bioactive Solvent Fractions of Moringa concanensis Nimmo Bark

Moringa concanensis Nimmo (Moringaceae) belongs to the same family of M. oleifera (miracle tree) and is a medicinal plant traditionally used by Indians to treat various ailments related to diabetes, tumours, inflammation, and blood pressure. Despite its versatility, the photoprotective properties of the plant remain unclear. This study revealed the UV-protective properties of its methanol bark extract and respective subfractions, chloroform, hexane, and ethyl acetate through total phenolic and flavonoid content (TPC & TFC), antioxidant (DPPH), sun protecting factor (SPF) value, and UV absorption spectra analysis. This study also investigated on the inhibitory effect of the tested samples on collagenases and elastase, which are well-known for their role in the skin. The cytotoxic and H2O2 scavenging properties of M. concanensis in 3T3-L1 cells were explored. Finally, the phytochemical profiling of the active fraction was conducted through UPLC-QTOF/MS analysis. Among the tested fractions, the chloroform fraction of M. concanensis showed the highest TPC (30.92 ± 0.71 mg GAE/DW), TFC (29.05 ± 0.09 mg QE/DW), and antioxidant properties (IC50-6.616 ± 1.90 μgml−1). Additionally, chloroform fraction demonstrated the highest SPF value, 10.46 at 200 μgml−1, compared to the other tested fractions. All the fractions showed a broad absorption spectrum covering both UVA and UVB ranges. The chloroform fraction of M. concanensis also showed collagenase (50%) and elastase (IC50-2.95 ± 1.23 μgml−1) inhibition properties similar to the positive control. Cytotoxic results revealed that the chloroform fraction of M. concanensis prevented the H2O2-induced oxidative damage in 3T3-L1 cells even at lower concentrations (1.56 μgml−1). UPLC-QTOF/MS analysis tentatively identified the presence of bioactive flavonoids and phenolics such as astragalin, quercetin, isoquercetin, and caffeic acid in the active fraction of M. concanensis bark. Overall, it is suggested that the chloroform fraction of M. concanensis bark has the potency to be used as an active ingredient in sunscreen products.

Separation of constituents from Bergenia stracheyi (Hook. F. & Thoms.) Engl. by high-speed countercurrent chromatography with elution mode and its antidiabetic and antioxidant in vitro evaluation

Diabetes, a metabolic disorder, is caused by a high blood sugar level. Diabetes is an increasing health issue and search for potent antidiabetic agents is desirable. Owing to its ethnomedicinal value, the Himalayan perennial herb Bergenia stracheyi (Hook. f. & Thoms.) Engl. (Saxifragaceae Juss) is used to treat diabetes. Herein, an efficient high-speed countercurrent chromatography with elution mode is reported for separation of active compounds from B. stracheyi. In current investigation, six main compounds including β-arbutin (1), bergenin (2), 6-O-galloylarbutin (3), gallic acid (4), 11-O-galloylbergenin (5), and (-)-epicatechin 3-O-gallate (6) with above 95% purity were efficiently separated in a single run using biphasic tert-butyl methyl ether/n-butanol/methanol/water (1:3:1:5, v/v/v/v) solvent system. The structures of these compounds were characterized using spectral techniques and compared with the literature. Antidiabetic and antioxidant activities evaluation of the study samples showed that β-arbutin (1) and 6-O-galloylarbutin (3) have a significant protective effect, especially at high dose against hydrogen peroxide induced oxidative injury. Our results might help further in-depth phytochemical and biological evaluation studies in search of potent antidiabetic compounds from B. stracheyi.

Phytochemical, Antibacterial and Antioxidant Activity Evaluation of Rhodiola crenulata

The chemical components, as well as the antibacterial and antioxidant activities of the essential oil (EO) and crude extracts prepared from Rhodiola crenulata were investigated. The essential oil was separated by hydrodistillation, and gas chromatography-mass spectrometry (GC-MS) was used to identify its constituents. A total of twenty-seven compounds was identified from the EO, and its major components were 1-octanol (42.217%), geraniol (19.914%), and 6-methyl-5-hepten-2-ol (13.151%). Solvent extraction and fractionation were applied for preparing the ethanol extract (crude extract, CE), petroleum ether extract (PE), ethyl acetate extract (EE), n-butanol extract (BE), and water extract (WE). The CE, EE and BE were abundant in phenols and flavonoids, and EE had the highest total phenol and total flavonoid contents. Gallic acid, ethyl gallate, rosavin and herbacetin were identified in the EE. The antibacterial activity results showed that the EO exhibited moderate inhibitory activity to the typical clinic bacteria, and EE exhibited the strongest antibacterial activity among the five extracts. For the compounds, ethyl gallate showed the strongest inhibitory activity to the test bacteria, and its minimum inhibitory concentration (MIC) value and minimum bactericidal concentration (MBC) value for all the tested bacteria was 0.24 mg/mL and 0.48 mg/mL, respectively. The results of antioxidant activity showed that both CE and EE exhibited strong antioxidant activities in the DPPH radical scavenging and Fe2+ reducing power tests, however, EO showed relatively weaker antioxidant ability. Ethyl gallate and rosavin exhibited excellent activity in the DPPH radical scavenging assay, and their IC50 value was 5.3 µg/mL and 5.9 µg/mL, respectively. Rosavin showed better reduction power activity than the other three compounds. These results could provide more evidence for the traditional use of R. crenulata, and would be helpful for improving its application further.