Evaluation of Anti-Melanogenesis Activity of Enriched Pueraria lobata Stem Extracts and Characterization of Its Phytochemical Components Using HPLC-PDA-ESI-MS/MS

Puerarin-A Promising Flavonoid: Biosynthesis, Extraction Methods, Analytical Techniques, and Biological Effects

Flavonoids, a variety of plant secondary metabolites, are known for their diverse biological activities. Isoflavones are a subgroup of flavonoids that have gained attention for their potential health benefits. Puerarin is one of the bioactive isoflavones found in the Kudzu root and Pueraria genus, which is widely used in alternative Chinese medicine, and has been found to be effective in treating chronic conditions like cardiovascular diseases, liver diseases, gastric diseases, respiratory diseases, diabetes, Alzheimer's disease, and cancer. Puerarin has been extensively researched and used in both scientific and clinical studies over the past few years. The purpose of this review is to provide an up-to-date exploration of puerarin biosynthesis, the most common extraction methods, analytical techniques, and biological effects, which have the potential to provide a new perspective for medical and pharmaceutical research and development.

Down-regulation of human papillomavirus E6 oncogene and antiproliferative effect of Schisandra chinensis and Pueraria lobata natural extracts on Hela cell line

ETHNOPHARMACOLOGICAL RELEVANCE

Cervical cancer is one of the most common malignancies in women that continues to be a public health problem worldwide. Human papillomavirus (HPV) infection is closely related as the causative agent of almost all cases of cervical cancer. Currently, there is no effective treatment for the persistence of HPV. Although vaccines have shown promising results in recent years, they are still a costly strategy for developing countries and have no therapeutic effect on existing infections, which is why the need arises to search for new strategies that can be used in treatment, suppressing oncogenic HPV and disease progression. Extracts of Schisandra Chinensis and Pueraria lobata have been used in traditional medicine, and it has been shown in recent years that some of their bioactive compounds have pharmacological, antioxidant, antitumor, apoptotic, and proliferation effects in HPV-positive cells. However, its mechanism of action has yet to be fully explored.

AIM OF THE STUDY

The following study aimed to determine the chemical composition, antioxidant activity, and potential antiproliferative and viral oncogene effects of natural extracts of S. chinensis and P. lobata on HPV-18 positive cervical cancer cells.

MATERIALS AND METHODS

The HPV-18-positive HeLa cells were treated for 24 and 48 h with the ethanolic extracts of S chinensis and P. lobata. Subsequently, cell viability was evaluated using the resazurin method, the effect on the cell cycle of the extracts (1.0, 10, and 100 μg/mL) was measured by flow cytometry, the gene of expression of the E6/E7, P53, BCL-2, and E2F-1 were determined by RT-PCR and the protein expression of p53, Ki-67, x|and Bcl-2 by immunohistochemistry. Additionally, the chemical characterization of the two extracts was carried out using LC-MS, and the total phenolics content (TPC), Total flavonoid content (TFC), and DPPH radical scavenging capacity were determined. Data were analyzed using the Mann-Whitney and Kruskal Wallis U test with GraphPad Prism 6 software.

RESULTS

The natural extracts of Schisandra chinensis and Pueraria lobata induced down-regulation of E6 HPV oncogene (p<0.05) and a strong up-regulation of P53 (p<0.05), E2F-1 (p<0.05), and Bcl-2 (p<0.05) gene expression. Simultaneously, the natural extracts tend to increase the p53 protein levels and arrest the cell cycle of HeLa in the G1/S phase (p<0.05). Investigated extracts were characterized by the occurrence of bioactive lignans and isoflavones in S. chinensis and P. lobata, respectively.

CONCLUSION

The extracts of S. chinensis and P. lobata within their chemical characterization mainly present lignan and isoflavone-type compounds, which are probably responsible for inhibiting the expression of the HPV E6 oncogene and inducing an increase in the expression of p53, Bcl -2 and E2F-1 producing cell cycle detection in S phase in HeLa cells. Therefore, these extracts are good candidates to continue studying their antiviral and antiproliferative potential in cells transformed by HPV.

The Mechanism of Peach Gum Polysaccharide Preventing UVB-Induced Skin Photoaging by Regulating Matrix Metalloproteinanse and Oxidative Factors

Exposure to ultraviolet light can cause oxidative damage and accelerate skin aging and is one of the main causes of skin aging. Peach gum polysaccharide (PG) is a natural edible plant component that has many biological activities, such as regulating blood glucose and blood lipids and improving colitis, as well as antioxidant and anticancer properties. However, there are few reports on the antiphotoaging effect of peach gum polysaccharide. Therefore, in this paper, we study the basic composition of the raw material peach gum polysaccharide and its ability to improve UVB-induced skin photoaging damage in vivo and in vitro. The results show that peach gum polysaccharide is mainly composed of mannose, glucuronic acid, galactose, xylose, and arabinose, and its molecular weight (Mw) is 4.10 × 10⁶ g/mol. The results of the in vitro cell experiments show that PG could significantly alleviate UVB-induced apoptosis of human skin keratinocytes, promote cell growth repair, reduce the expression of intracellular oxidative factors and matrix metal collagenase, and improve the extent of oxidative stress repair. Moreover, the results from the in vivo animal experiments showed that PG could not only effectively improve the phenotype of UVB-induced photoaged skin in model mice but also significantly improve their oxidative stress status, regulate the contents of ROS and the levels of SOD and CAT, and repair the oxidative skin damage induced by UVB in vivo. In addition, PG improved UVB-induced photoaging-mediated collagen degradation in mice by inhibiting the secretion of matrix metalloproteinases. The above results indicate that peach gum polysaccharide has the ability to repair UVB-induced photoaging and may be used as a potential drug and antioxidant functional food to resist photoaging in the future.

Preclinical studies on melanogenesis proteins using a resveratrol-nanoformula as a skin whitener

A naturally occurring polyphenol called trans-resveratrol has received a lot of attention due to its possible health advantages for humans. The low solubility of trans-resveratrol and its isomerization upon UV exposure strongly limit its application as a skin-whitening agent. In the present study, to increase trans-resveratrol solubility, a new nanoformula was created by combining hydrophilic surfactants and oils. Trans-Resveratrol nanoformula has been prepared, characterized, and applied as a skin-whitening agent on the dorsal skin of Guinea pigs. The optimized trans-resveratrol nanoformula with a particle size of 63.49 nm displayed a single peak and a polydispersity index [0.36 ± 0.02]. In addition, the zeta potential of the optimized formula was -30.4 mV, confirming the high stability of this nanoformula. The melanin contents in the trans-resveratrol nanoformula-treated group were substantially lower than those of the control and the blank nanoformula-treated groups after staining of the dorsal skins [black areas] of guinea pigs with Fontana Mountain dye. The pigmentation index in the control, blank nanoformula, and optimized trans-resveratrol nanoformula were 329.4 ± 36.9, 335.8 ± 71.4, and 124.8 ± 19.6 respectively. Confirming this finding, immunohistochemistry analysis of skin tissues revealed that the expressions of melanogenesis-regulating proteins such as tyrosinase and microphthalmia-associated transcription factor were down-regulated. The safety of topical application of trans-resveratrol nanoformula was validated by no changes in free radical levels and oxidative stress markers proteins in the livers and kidneys of guinea pigs at the end of the experiment. Conclusions: A novel trans-resveratrol nanoformula as well as the mechanism whereby it promotes skin whitening effects were presented. Furthermore, the study illustrated that trans-resveratrol nanoformula is safe, non-toxic, and can be applied for skin whitening, although more research on human skin is needed.

Extraction and Concentration of Waste Pueraria lobata Stems with Antioxidants and Anti-Melanogenesis Activity as a Novel Skin Whitening Agent for Natural Cosmetic Prototypes

The root of Pueraria lobata (Willd.) is used commercially in different products, including dietary supplements, cosmetics, and teas, but its stem part is rarely used and studied. Therefore, this study evaluated the antioxidant and anti-melanogenesis activities of the bioactive fraction of P. lobata stem and investigated whether the activated carbon decolorization technique would have an impact on its activity and chemical composition. We observed that the dichloromethane fraction of P. lobata stem (DCM-PLS) has excellent antioxidant and anti-melanin synthesis activity at a concentration of 50 μg/mL. For the investigation of the anti-melanogenesis mechanism, we evaluated the mRNA expression of tyrosinase, which was depressed by the DCM-PLS. Daidzin was identified as the main active ingredient in DCM-PLS by using a high-performance liquid chromatography-diode array detector-hyphenated with tandem mass spectrometry. In addition, the activated carbon decolorization technology has no negative impact on the main components and bioactivity of DCM-PLS. DCM-PLS also did not induce any skin response in the human skin safety test. Collectively, DCM-PLS could be used as a natural type of skin-whitening agent in skin care products.

Nomilin from Yuzu Seed Has In Vitro Antioxidant Activity and Downregulates Melanogenesis in B16F10 Melanoma Cells through the PKA/CREB Signaling Pathway

Yuzu (Citrus junos) is a citrus plant native to Asian countries, including Korea, Japan, and China. Yuzu peel and seed contain abundant vitamin C, citric acid, and polyphenols. Although the antioxidative and antimelanogenic activities of other citrus fruits and yuzu extract have been reported, the tyrosinase inhibitory activity of the limonoid aglycone contained in yuzu seed extract is unknown. We separated yuzu seeds into the husk, shell, and meal and evaluated antioxidant activity of each. The limonoid glucoside fraction of the husk identified nomilin, a novel tyrosinase inhibitor. We performed tyrosinase inhibitory activity and noncompetitive inhibition assays and docking studies to determine nomilin binding sites. Furthermore, we evaluated the antioxidative mechanism and antimelanogenic activity of nomilin in B16F10 melanoma cells. The concentration of nomilin that did not show toxicity was <100 µg/mL. Nomilin suppressed protein expression of TYR, TRP-1, TRP-2, and microphthalmia-associated transcription factor (MITF) in a concentration-dependent manner. Nomilin significantly reduced the levels of p-CREB and p-PKA at the protein level and decreased the levels of skin-whitening-related factors MITF, tyrosinase, TRP-1, and TRP-2 at the mRNA level in a concentration-dependent manner. Thus, nomilin from yuzu seed husk can be used as a skin-whitening agent in cosmetics.

The Modulation of Melanogenesis in B16 Cells Upon Treatment with Plant Extracts and Isolated Plant Compounds

Plants are a rich source of secondary metabolites that exhibit numerous desired properties. The compounds may influence the biology of melanocytes, pigment cells that produce melanin, by modulating numerous signaling pathways, including cAMP/PKA, MAPKs and PI3K/AKT. Its downstream target is microphthalmia-associated transcription factor, responsible for the expression of the tyrosinase enzyme, which plays a major role in melanogenesis. Therefore, this literature review aims to provide insights related to melanogenesis modulation mechanisms of plant extracts and isolated plant compounds in B16 cells. Database searches were conducted using online-based library search instruments from 2012 to 2022, such as NCBI-PubMed and Google Scholar. Upregulation or downregulation of signaling pathways by phytochemicals can influence skin hypo- and hyperpigmentation by changing the level of melanin production, which may pose a significant cosmetic issue. Therefore, plant extracts or isolated plant compounds may be used in the therapy of pigmentation disorders.

Inhibitory Effect of Chlorogenic Acid Analogues Comprising Pyridine and Pyrimidine on α-MSH-Stimulated Melanogenesis and Stability of Acyl Analogues in Methanol

In continuation of studies for α-MSH stimulated melanogenesis inhibitors, we have evaluated the design, synthesis, and activity of a new series of chlorogenic acid (CGA) analogues comprising pyridine, pyrimidine, and diacyl derivatives. Among nineteen synthesized compounds, most of them (fifteen) exhibited better inhibitions of melanin formation in B16 melanoma cells. The results illustrated that a pyridine analogue 6f and a diacyl derivative 13a of CGA showed superior inhibition profiles (IC50: 2.5 ± 0.7 μM and 1.1 ± 0.1 μM, respectively) of α-MSH activities than positive controls, kojic acid and arbutin (IC50: 54 ± 1.5 μM and 380 ± 9.5 μM, respectively). The SAR studies showed that both -CF3 and -Cl groups exhibited better inhibition at the meta position on benzylamine than their ortho and para positions. In addition, the stability of diacyl analogues of CGA in methanol monitored by HPLC for 28 days indicated the steric bulkiness of acyl substituents as a key factor in their stability.