The extract of Thujae occidentalis semen inhibited 5alpha-reductase and androchronogenetic alopecia of B6CBAF1/j hybrid mouse

Justicia procumbens prevents hair loss in androgenic alopecia mice

The plant Justicia procumbens is traditionally used in Asia to treat fever, cough, and pain. Previous studies have reported its anticancer and anti-asthmatic properties. However, its potential for preventing androgenic alopecia (AGA) has not yet been reported. AGA is a widespread hair loss condition primarily caused by male hormones. In this study, we examined the hair loss-preventing effects of an aqueous extract of J. procumbens (JPAE) using human hair follicle dermal papilla cell (HFDPC) and a mouse model of testosterone-induced AGA. JPAE treatment increased HFDPC proliferation by activating the Wnt/β-catenin signaling pathway. Additionally, JPAE increased the expression of Wnt targets, such as cyclin D1 and VEGF, by promoting the translocation of β-catenin to the nucleus. Administration of JPAE reduced hair loss, increased hair thickness, and enhanced hair shine in an AGA mouse model. Furthermore, it increased the expression of p-GSK-3β and β-catenin in the dorsal skin of the mice. These findings imply that JPAE promotes the proliferation of HFDPC and prevents hair loss in an AGA mouse model. JPAE can therefore be used as a functional food and natural treatment option for AGA to prevent hair loss.

Efficacy of Asymmetric siRNA Targeting Androgen Receptors for the Treatment of Androgenetic Alopecia

Asymmetric small interfering RNAs (asiRNAs) that mediate RNA interference have been investigated for therapeutic use in various tissues, including skin tissue. Androgenetic alopecia (AGA) is caused by a combination of genetic factors, resulting in sensitivity to dihydrotestosterone (DHT), which binds to the androgen receptor (AR) to mediate a series of biomolecular changes leading to hair loss. This study aimed to evaluate the therapeutic potential of a cell-penetrating, AR-targeting asiRNA (cp-asiAR) for AGA treatment, which was designed to silence the AR gene. AGA mouse models were developed by stimulation with DHT, and ex vivo human scalp tissues were also used for analysis. Cp-asiAR-mediated changes in mRNA expression and protein levels of AR were assessed along with the examination of phenotypic improvements in mouse model of AGA. We also assessed downstream signaling associated with AR in primary human dermal papilla (DP) cells. Several cp-asiARs were screened for selecting the optimal sequence of AR using cell lines in vitro. A cholesterol-conjugated, chemically modified cp-asiAR candidate was optimized under passive uptake conditions in vitro. Intradermal cp-asiAR injection efficiently reduced mRNA and protein levels corresponding to AR in mouse models. Moreover, cp-asiAR injection promoted hair growth in mouse models with DHT-induced AGA. In ex vivo human hair follicle culture, the proportion of telogen hair decreased, and the mean hair bulb diameter increased in the cp-asiAR-treated group. In isolated primary human DP cells, AR expression was effectively downregulated by cp-asiAR. Furthermore, cp-asiAR attenuated DHT-mediated increases in interleukin-6, transforming growth factor-β1, and dickkopf-1 levels. No significant toxicity was observed in DP cells after cp-asiAR treatment. Cp-asiAR treatment showed effective downregulation of AR expression and prevention of DHT-mediated alterations in the hair cycle and hair diameter, indicating its potential as a novel therapeutic option for AGA.

An appraisal of laboratory models of androgenetic alopecia: A systematic review

Background

Androgenetic alopecia (AGA) is the most common form of non‐scarring alopecia in humans. Several studies have used different laboratory models to study the pathogenesis and interventions for AGA. These study models have proved beneficial and have led to the approval of two drugs. However, the need to build on existing knowledge remains by examining the relevance of study models to the disease.

Objective

We sought to appraise laboratory or pre‐clinical models of AGA.

Method

We searched through databases (PubMed, ScienceDirect, Web of Science, World CAT, Scopus and Google Scholar) for articles on AGA‐related studies from 1942 to March 2019 with a focus on study models.

Results

The search rendered 101 studies after screening and deduplication. Several studies (70) used in vitro models, mostly consisting of two‐dimensional monolayer cells for experiments involving the characterization of androgen and 5‐alpha reductase (5AR) and inhibition thereof, the effects of dihydrotestosterone (DHT) and biomarker(s) of AGA. Twenty‐seven studies used in vivo models of mice and monkeys to investigate DHT synthesis, the expression and inhibition of 5AR and hair growth. Only four studies used AGA‐related or healthy excisional/punch biopsy explants as ex vivo models to study the action of 5AR inhibitors and AGA‐associated genes. No study used three‐dimensional [3‐D] organoids or organotypic human skin culture models.

Conclusion

We recommend clinically relevant laboratory models like human or patient‐derived 3‐D organoids or organotypic skin in AGA‐related studies. These models are closer to human scalp tissue and minimize the use of laboratory animals and could ultimately facilitate novel therapeutics.

Anti-Inflammatory, Thrombolytic and Hair-Growth Promoting Activity of the n-Hexane Fraction of the Methanol Extract of Leea indica Leaves

The anti-inflammatory, thrombolytic, and hair growth-promoting activity of the n-hexane fraction from the methanol extract of Leea indica (NFLI) leaves was investigated. NFLI showed significant inhibition of hemolysis and protein denaturation, and exhibited a concentration-dependent thrombolytic activity. When applied topically to mice at concentrations of 10, 1, 0.1%, NFLI demonstrated a significant increase in average hair length (p < 0.001) compared with untreated animals. NFLI (1% concentration) exhibited the highest percentage of hair regrowth on day 7, 14 and 21 (81.24, 65.60, and 62.5%, respectively). An in silico study was further conducted to predict the binding affinity of phytochemicals previously reported in L. indica towards PGD₂ synthase (PDB ID: 2VD1), an enzyme that catalyses the isomerisation of prostaglandin H₂ to PGD₂ which is involved in hair loss. Phthalic acid, farnesol, n-tricosane, n-tetracosane, and n-heptacosane showed the best ligand efficiencies towards PGD₂ synthase and their intermolecular interactions were visualised using BIOVIA Discovery Studio Visualizer. Our results indicate that L. indica could represent a promising natural alternative to tackle alopecia.

Effects on Steroid 5-Alpha Reductase Gene Expression of Thai Rice Bran Extracts and Molecular Dynamics Study on SRD5A2

Simple Summary

Dihydrotestosterone (DHT), the most potent androgen hormone, is an important aetiologic factor of androgenetic alopecia (AGA), or hair loss. Steroid 5-alpha reductases (SRD5As) increase DHT production in the scalp hair follicles, resulting in hair thinning and hair loss. Even though synthetic SRD5A inhibitors (finasteride and dutasteride) are effective in treating AGA, they cause adverse effects. This has led to an increased interest in alternative treatments from natural sources. The value of Thai rice bran has increased because several of its components may have use in AGA treatment. This study aimed to compare the suppression of the expression of SRD5A genes (type 1–3) exerted by several Thai rice bran extracts and investigate the interactional mechanism of their components towards SRD5A type 2. Tubtim Chumphae rice bran (TRB) had the highest sum of overall bioactive compounds. Among all extracts, the expression of SRD5A genes was suppressed by TRB as well as finasteride. In silico simulation showed that α-tocopherol had the greatest interaction with SRD5A type 2. Our findings identified α-tocopherol as the key bioactive in TRB; it could be developed as an anti-hair loss product.

Abstract

Steroid 5-alpha reductases (SRD5As) are responsible for the conversion of testosterone to dihydrotestosterone, a potent androgen, which is the aetiologic factor of androgenetic alopecia. This study aimed to compare the SRD5A gene expression suppression activity exerted by Thai rice bran extracts and their components and investigate the interactional mechanism between bioactive compounds and SRD5A2 using molecular dynamics (MD) simulation. Bran of Oryza sativa cv. Tubtim Chumphae (TRB), Yamuechaebia Morchor (YRB), Riceberry (RRB), and Malinil Surin (MRB), all rice milling by-products, was solvent-extracted. The ethanolic extract of TRB had the highest sum of overall bioactive compounds (γ-oryzanol; α-, β-, and γ-tocopherol; phenolics; and flavonoids). Among all extracts, TRB greatly downregulated the expression of SRD5A1, SRD5A2, and SRD5A3; there were no significant differences between TRB and finasteride regarding SRD5A suppression. The linear relationship and principal component analysis supported that the α-tocopherol content was correlated with the SRD5A suppression exerted by TRB. Furthermore, MD simulation demonstrated that α-tocopherol had the highest binding affinity towards SRD5A2 by interacting with residues Phe118 and Trp201. Our findings indicate that α-tocopherol effectively downregulates the expression of SRD5A genes and inhibits SRD5A2 activity, actions that are comparable to standard finasteride. TRB, a source of α-tocopherol, could be developed as an anti-hair loss product.

Phytochemicals With Anti 5-alpha-reductase Activity: A Prospective For Prostate Cancer Treatment

Prostate cancer (CaP) is one of the leading causes of death in men worldwide. Much attention has been given on its prevention and treatment strategies, including targeting the regulation of 5-alpha-Reductase (5αR) enzyme activity, aimed to limit the progression of CaP by inhibiting the conversion of potent androgen dihydrotestosterone from testosterone that is thought to play a role in pathogenesis of CaP, by using the 5-alpha-Reductase inhibitors (5αRis) such as finasteride and dutasteride. However, 5αRis are reported to exhibit numerous adverse side effects, for instance erectile dysfunction, ejaculatory dysfunction and loss of libido. This has led to a surge of interest on plant-derived alternatives that might offer favourable side effects and less toxic profiles. Phytochemicals from plants are shown to exhibit numerous medicinal properties in various studies targeting many major illnesses including CaP. Therefore, in this review, we aim to discuss the use of phytochemicals namely phytosterols, polyphenols and fatty acids, found in various plants with proven anti-CaP properties, as an alternative herbal CaP medicines as well as to outline their inhibitory activities on 5αRs isozymes based on their structural similarities with current 5αRis as part of CaP treatment approaches.

Dihydrotestosterone-induced hair regrowth inhibition by activating androgen receptor in C57BL6 mice simulates androgenetic alopecia

Androgenic alopecia (AGA), also known as male pattern baldness, is one of the most common hair loss diseases worldwide. The main treatments of AGA include hair transplant surgery, oral medicines, and LDL laser irradiation, although no treatment to date can fully cure this disease. Animal models play important roles in the exploration of potential mechanisms of disease development and in assessing novel treatments. The present study describes androgen receptor (AR) in C57BL/6 mouse hair follicles that can be activated by dihydrotestosterone (DHT) and translocate to the nucleus. This led to the design of a mouse model of androgen-induced AGA in vivo and in vitro. DHT was found to induce early hair regression, hair miniaturization, hair density loss, and changes in hair morphology in male C57BL/6 mice. These effects of DHT could be partly reversed by the AR antagonist bicalutamide. DHT had similar effects in an ex vivo model of hair loss. Evaluation of histology, organ culture, and protein expression could explain the mechanism by which DHT delayed hair regrowth.

A comprehensive review of biochemical factors in herbs and their constituent compounds in experimental studies on alopecia

ETHNOPHARMACOLOGICAL RELEVANCE

Alopecia is a chronic condition that may cause emotional and psychological distress to patients, which may significantly impact a patient's quality of life. As conventional treatments have only a transient therapeutic effect and result in unwanted side effects, many patients have attempted to find therapeutic herbs or compounds that function as safer and more potent treatments for alopecia. Many such herbs have been used in complementary and alternative medicine (CAM) for centuries; however, there is a lack of information on the therapeutic mechanisms of herbs used for the treatment of alopecia.

AIM OF THE STUDY

The aim of this review was to perform a critical assessment of the methods and results of experimental studies related to alopecia and to provide the potential mechanisms of action of herbs and their constituent compounds used in the identified studies, in particular, in relation to the stages of the cell cycle. We hope to better guide the clinical application and scientific research of herbs for the treatment of alopecia.

MATERIALS AND METHODS

We reviewed experimental studies to determine the methods used and the mechanism of action of the herbs and constituent compounds. Databases, including Medline (via PubMed), EMBASE, OASIS, and RISS, were searched for the following keywords: "medicinal plants," "alopecia," "alopecia areata," "androgenetic alopecia," "animal experiment," and "in vitro study." We also assessed the risks of bias, toxicity, and taxonomy to determine the quality of information.

RESULTS

C57BL/6 mice and human dermal papilla cells were the most commonly used models for in vivo and in vitro studies, respectively. Many herbs and their constituent compounds were used to treat alopecia by managing the hair cycle, keratinocyte proliferation, apoptosis, angiogenesis, hormones, and inflammation. These compounds prolong the anagen phase, shorten the transition from the telogen to phase anagen, and inhibit premature catagen phase.

CONCLUSIONS

This review has further elucidated the therapeutic mechanisms of herbs and their constituent compounds that are relevant to alopecia and discussed the effectiveness of using herbal treatments. There is a need to develop evidence regarding the quality control, taxonomy, and toxicology of these compounds. Such improvements will provide a better quality of evidence to ensure the efficacy and safety of herbs and compounds used for the treatment of alopecia.

Expression in Escherichia Coli, Purification, and Functional Reconstitution of Human Steroid 5α-Reductases

The potent androgen 5α-dihydrotestosterone irreversibly derives from testosterone via the activity of steroid 5α-reductases (5αRs). The major 5αR isoforms in most species, 5αR1 and 5αR2, have not been purified to homogeneity. We report here the heterologous expression of polyhistidine-tagged, codon-optimized human 5αR1 and 5αR2 cDNAs in Escherichia coli. A combination of the nonionic detergents Triton X-100 and Nonidet P-40 enabled solubilization of these extremely hydrophobic integral membrane proteins and facilitated purification with affinity and cation-exchange chromatography methods. For functional reconstitution, we incorporated the purified isoenzymes into Triton X-100-saturated dioleoylphosphatidylcholine liposomes and removed excess detergent with polystyrene beads. Kinetic studies indicated that the 2 isozymes differ in biochemical properties, with 5αR2 having a lower apparent Km for testosterone, androstenedione, progesterone, and 17-hydroxyprogesterone than 5αR1; however, 5αR1 had a greater capacity for steroid conversion, as reflected by a higher Vmax than 5αR2. Both enzymes preferred progesterone as substrate over other steroids, and the catalytic efficiency of purified reconstituted 5αR2 exhibited a sharp pH optimum at pH 5. Intriguingly, we found that the prostate-cancer drug-metabolite 3-keto-∆ 4-abiraterone is metabolized by 5αR1 but not 5αR2, which may serve as a structural basis for isoform selectivity and inhibitor design. The functional characterization results with the purified reconstituted isoenzymes paralleled trends obtained with HEK-293 cell lines stably expressing native 5αR1 and 5αR2. Access to purified human 5αR1 and 5αR2 will advance studies of these important enzymes and might help to clarify their contributions to steroid anabolism and catabolism.

Jagged1 and Epidermal Growth Factor Promoted Androgen-Suppressed Mouse Hair Growth In Vitro and In Vivo

Recent studies have reported that T-reg cells are intimately linked with hair follicles in a stage-dependent manner and play an important role in hair follicle cycling and regeneration in murine skin. Further study revealed that T-reg cell's regulation of hair follicle growth is through its preferential expression of the Notch ligand Jagged-1 (Jag1), which facilitates hair follicle regeneration. However, the role of Jag1 in androgen-suppressed hair growth is yet to be investigated. In addition, although epidermal growth factor (EGF) is a mitogen for cells including skin cells, whether it works synergistically with Jag1 to enhance hair follicle development is unknown. The current study intended to investigate effects of topical application of Jag1 on androgen-suppressed hair growth, and to determine the potential synergistic effect of EGF and Jag1 in this process in vivo. Fifty mice were depilated at the dorsal back area to achieve synchronized anagen development, and randomly divided into five groups with the following topical treatments control for 14 days; testosterone to induce androgenetic alopecia; Jagged1 (testosterone + Jagged1); EGF (testosterone + EGF); and Jagged1 + EGF (testosterone + Jagged1 + EGF). It was found that EGF and Jag1 by itself respectively, did not promote androgen-suppressed hair growth significantly. This stimulating effect was enhanced in the presence of both EGF and Jagged1 (p < 0.05). The hair growth promoting effect was accompanied by better follicle growth, which is associated with increased cell proliferation in the hair follicle and altered the expression of genes that are important in hair follicular cell proliferation and differentiation. Our results provide insights into the therapeutic potential of these peptides for androgenetic alopecia.

In vivo and in vitro evaluation of hair growth potential of Cacumen Platycladi, and GC-MS analysis of the active constituents of volatile oil

ETHNOPHARMACOLOGICAL RELEVANCE

Cacumen Platycladi (CP) is the leaves of Platycladus orientalis which has been traditionally used to resist alopecia and promote hair growth. However, no study has been reported on the effects of CP on proliferation of dermal papilla cells (DPCs). And there is also no complete and systematic research on hair re-growth efficacies of CP.

AIM OF THE STUDY

To evaluate the hair-growth activity of their extracts on the proliferation of DPCs and the promotion of hair reproduction in C57BL/6 mice.

MATERIALS AND METHODS

For the DPCs, different extract fractions of CP were investigated. The hair growth effect of CP volatile oil on C57BL/6 mice was evaluated for 28 days. Meanwhile, the chemical constituents of the volatile oil from Cacumen Platycladi were isolated and identified by GC-MS.

RESULTS

The study showed that the extracts of CP could promote the proliferation of DPCs, and the activity of volatile oil was the best. CP volatile oil (100 μg/mL) resulted in stronger proliferation of DPCs by 239.8% compared with control (100%) and minoxidil (130.3%) during the 48 h incubation. And no obvious cytotoxic activity was observed when volatile oil was dosed up to 500 μg/mL. At different growth stages, mice treated with 0.2 g/kg CP volatile oil required shorter time than 2% minoxidil. Hair length for 0.2 g/kg CP volatile oil treated group was longer than those of minoxidil and control. Further histological observation indicated that CP volatile oil could prolonged the anagen phase of hair follicles. Moreover, thirty four components, with contents of 81.9% of the total volatile oils, were separaed and identified.

CONCLUSION

The CP volatile oil may have the potential therapeutic agent for the treatment of alopecia.

Discovery of Natural Steroid 5 Alpha-Reductase Inhibitors

Human steroid 5 alpha-reductases (S5αRs) and NADPH irreversibly reduce testosterone to the more potent dihydrotestosterone (DHT). S5αR inhibitors are useful treatments for DHT-dependent diseases, including benign prostatic hyperplasia, androgenic alopecia and hair growth, and acne. There are three S5αR isozymes, and there is a need for safer and more isozyme selective inhibitors than finasteride and dutasteride currently licensed. In this study, we review the methods used to screen for S5αR inhibitory activity and describe studies that characterize the ability of herbal preparations and their constituents to inhibit S5αRs. We identified enormous variations between studies in IC₅₀s for finasteride and dutasteride used as standards. Accordingly, we make several recommendations: Stable isozyme specific transfection systems need creating a standardized enzyme/microsome preparation and all three isozymes, as well as androgen receptor binding, should be tested; agreed reaction conditions, especially the substrate concentrations, and separation/quantitation method optimized for high throughput screening; systematic screening of herbal compounds and most extensive use of leads to develop more potent and isozyme specific inhibitors.

Hair Regenerative Mechanisms of Red Ginseng Oil and Its Major Components in the Testosterone-Induced Delay of Anagen Entry in C57BL/6 Mice

Hair loss (alopecia) is a universal problem for numerous people in the world. The present study was conducted to investigate the effects of red ginseng oil (RGO) and its major components on hair re-growth using testosterone (TES)-induced delay of anagen entry in C57BL/6 mice and their mechanisms of action. Seven-week-old C57BL/6 mice were daily treated with TES for 1 h prior to topical application of 10% RGO, 1% linoleic acid (LA), 1% β-sitosterol (SITOS), or 1% bicyclo(10.1.0)tridec-1-ene (BICYCLO) once a day for 28 days. Hair regenerative capacity was significantly restored by treatment of RGO and its major compounds in the TES-treated mice. Histological analysis showed that RGO along with LA and SITOS but not BICYCLO promoted hair growth through early inducing anagen phase that was delayed by TES in mice. Treatment of mice with RGO, LA, or SITOS up-regulated Wnt/β-catenin and Shh/Gli pathways-mediated expression of genes such as β-catenin, Lef-1, Sonic hedgehog, Smoothened, Gli-1, Cyclin D1, and Cyclin E in the TES-treated mice. In addition, RGO and its major components reduced the protein level of TGF-β but enhanced the expression of anti-apoptotic protein Bcl-2. These results suggest that RGO is a potent novel therapeutic natural product for treatment of androgenic alopecia possibly through hair re-growth activity of its major components such as LA and SITOS.

Mechanism of action of herbs and their active constituents used in hair loss treatment

This article discusses the mechanisms via topically applied products containing herbs and their active constituents affect the hair growth process. It was reported that the mechanisms involving (1) insulin-like growth factor-I (IGF-I), (2) vascular endothelial growth factor (VEGF), (3) epidermal growth factor (EGF), (4) fibroblast growth factor 2 (FGF-2), (5) endothelial nitric oxide synthase (eNOS), (6) Wnt/β-catenin signalling pathway, (7) prostaglandin E (PGE), (8) prostaglandin F (PGF) stimulate hair growth, whereas the mechanisms engaging (1) 5α-reductase and dihydrotestosterone (DHT), (2) transforming growth factor beta (TGF-β), (3) fibroblast growth factor 5 (FGF-5), (4) prostaglandin D₂ (PGD₂) inhibit hair growth. The knowledge summarized in the paper may be an inspiration to create new preparations for the treatment of hair loss.

Drug discovery for alopecia: gone today, hair tomorrow

INTRODUCTION

Hair loss or alopecia affects the majority of the population at some time in their life, and increasingly, sufferers are demanding treatment. Three main types of alopecia (androgenic [AGA], areata [AA] and chemotherapy-induced [CIA]) are very different, and have their own laboratory models and separate drug-discovery efforts.

AREAS COVERED

In this article, the authors review the biology of hair, hair follicle (HF) cycling, stem cells and signaling pathways. AGA, due to dihydrotesterone, is treated by 5-α reductase inhibitors, androgen receptor blockers and ATP-sensitive potassium channel-openers. AA, which involves attack by CD8(+)NK group 2D-positive (NKG2D(+)) T cells, is treated with immunosuppressives, biologics and JAK inhibitors. Meanwhile, CIA is treated by apoptosis inhibitors, cytokines and topical immunotherapy.

EXPERT OPINION

The desire to treat alopecia with an easy topical preparation is expected to grow with time, particularly with an increasing aging population. The discovery of epidermal stem cells in the HF has given new life to the search for a cure for baldness. Drug discovery efforts are being increasingly centered on these stem cells, boosting the hair cycle and reversing miniaturization of HF. Better understanding of the molecular mechanisms underlying the immune attack in AA will yield new drugs. New discoveries in HF neogenesis and low-level light therapy will undoubtedly have a role to play.

Potential targets in the discovery of new hair growth promoters for androgenic alopecia

INTRODUCTION

Androgenic alopecia (AGA) is the major type of scalp hair loss affecting 60 - 70% of the population worldwide. It is caused by two potent androgens, namely testosterone (T) and 5α-dihydrotestosterone (5α-DHT). Till date, only two FDA-approved synthetic drugs, minoxidil and finasteride, are used to cure AGA with only 35 and 48% success, respectively; therefore, a search for new drug based on the mechanism of androgens action is still needed.

AREAS COVERED

Relevant literature was reviewed to identify current therapeutic targets and treatments for AGA. The potential targets are classified into three categories: i) 5α-reductase; ii) androgen receptor and iii) growth-factor-producing genes related to hair growth.

EXPERT OPINION

Relevant assay systems using the right targets are required in order to obtain specific and effective drugs for AGA treatment. It is unlikely that single targeted agents will be sufficient for treating AGA, and therefore, it would be a challenge to obtain compounds with multiple activities.

Hair growth-promoting activity of hot water extract of Thuja orientalis

BACKGROUND

Thuja orientalis has been traditionally used to treat patients who suffer from baldness and hair loss in East Asia. The present study sought to investigate the hair growth-promoting activity of T. orientalis hot water extract and the underlying mechanism of action.

METHODS

After T. orientalis extract was topically applied to the shaved dorsal skin of telogenic C57BL/6 N mice, the histomorphometric analysis was employed to study induction of the hair follicle cycle. To determine the effect of T. orientalis extract on the telogen to anagen transition, the protein expression levels of β-catenin and Sonic hedgehog (Shh) in hair follicles were determined by immunohistochemistry.

RESULTS

We observed that T. orientalis extract promoted hair growth by inducing the anagen phase in telogenic C57BL/6 N mice. Specifically, the histomorphometric analysis data indicates that topical application of T. orientalis extract induced an earlier anagen phase and prolonged the mature anagen phase, in contrast to either the control or 1% minoxidil-treated group. We also observed increases in both the number and size of hair follicles of the T. orientalis extract-treated group. Moreover, the immunohistochemical analysis reveals earlier induction of β-catenin and Shh proteins in hair follicles of the T. orientalis extract-treated group, compared to the control or 1% minoxidil-treated group.

CONCLUSION

These results suggest that T. orientalis extract promotes hair growth by inducing the anagen phase in resting hair follicles and might therefore be a potential hair growth-promoting agent.

Techniques for the discovery and evaluation of drugs against alopecia

INTRODUCTION

Hair care, color and style play an important role in physical appearance and self-perception. Hair loss or alopecia is a common dermatological and affective disorder. Factors contributing to alopecia include genetic predisposition, hormonal factors, disease status, side effects of chemotherapeutic agents and stress. To keep pace with the demand for drugs for alopecia, attempts are being made to explore drugs with hair-growth-promotion activity. To explore and evaluate these, it is necessary to be familiar with the basics and the availability and suitability of techniques and experimental models of hair growth activity assessment.

AREAS COVERED

Basic and advanced techniques and models for assessing hair growth activity. A variety of pharmacological models of hair growth are reviewed. This review will help in selecting a suitable, relevant, inexpensive, easy and reliable model for hair growth assessment.

EXPERT OPINION

There is a need to identify the genes involved in hair follicle growth for the production of more effective animal models of the disorder. Standardization of pharmacological models will also be essential for better comparison and validation of results. Recently developed hair follicle organ culture models are a suitable, relevant and inexpensive alternative to traditional whole-animal pharmacological models and will, largely, replace whole-animal systems in the future.

5α-reductase inhibition and hair growth promotion of some Thai plants traditionally used for hair treatment

ETHNOPHARMACOLOGICAL RELEVANCE

Many Thai traditional herbs have been used for hundreds of years for hair treatment and nourishment, including hair loss. However, scientific evidence about their mechanisms of action has not yet been elucidated.

AIMS OF THE STUDY

The purpose of this research is to define the possible mechanisms involved in hair loss treatment of the selected plants by determining the 5α-reductase enzyme inhibition and hair growth promoting activities, and the relationship between these two activities.

MATERIALS AND METHODS

Seventeen Thai plants traditionally used for hair treatment were selected. The plants were dried, ground and extracted by maceration with ethyl alcohol. These extracts were further tested for 5α-reductase inhibition using enzymes from rat livers. Hair growth promoting activity was tested in C57BL/6 mice.

RESULTS

Carthamus tinctorius L. was the most potent 5α-reductase inhibitor, with a finasteride equivalent 5α-reductase inhibitory activity (FEA) value of 24.30±1.64 mg finasteride equivalent per 1g crude extract. Phyllanthus emblica L. was the second most potent inhibitor, with FEA of 18.99±0.40. Rhinacanthus nasutus (L.) Kurz. was the least potent 5α-reductase inhibitor (FEA 10.69±0.96). Carthamus tinctorius also was the most potent hair growth promoter in C57BL/6 mice. There were strong relationships between 5α-reductase inhibitory activity and hair growth promoting activity (r=0.719), and between 5α-reductase inhibitory activity and hair follicle count (r=0.766).

CONCLUSIONS

Ethanolic extract of Carthamus tinctorius was the most potent 5α-reductase inhibitor and hair growth promoter. This discovery may lead to the development of new alternative medicines for hair loss prevention and treatment.

Effects of topical application of EGCG on testosterone-induced hair loss in a mouse model

We investigated the effect of topical epigallocatechin-3-gallate (EGCG) on testosterone (T)-induced hair loss in mice. Marked hair loss was observed at the T-injected site, and topical EGCG significantly reduced the hair loss (P < 0.05). TUNEL staining showed apoptosis of follicular epithelial cells in the T-injected groups where topical EGCG was found to significantly diminish T-induced apoptosis (P < 0.05). Topical EGCG down-regulated the T-induced expression of androgen receptor but did not down-regulate 17β-hydroxysteroid dehydrogenase (HSD) and three β-HSD expression. Analysis using liquid chromatography tandem mass spectrometry (LC-MS/MS) on serum and tissue samples revealed no significant difference in T and dihydrotestosterone concentrations between the T-injected and T + EGCG groups. Thus, we found that T injection in a mouse model induces hair loss by apoptosis of the hair follicles rather than through the androgen metabolic pathway and also saw that T-induced apoptosis of hair follicles was reduced by topical EGCG.

Development and evaluation of polyherbal formulation for hair growth?promoting activity

BACKGROUND

Cuscuta reflexa (Roxb.), Citrullus colocynthis (Schrad.), and Eclipta alba (Hassk.) are traditionally acclaimed herbs for their hair growth-promoting potential. Aim In the present study, it was envisaged to prepare herbal formulations containing petroleum ether extracts of the three herbs in varying ratio and evaluating the formulations for the hair growth-promoting activity.

METHODS

The formulations as well as minoxidil (2%) solution (positive control) were applied topically on shaved skin of rats, and the time required for initiation and completion of hair growth cycle was recorded.

RESULTS AND CONCLUSIONS

Hair growth initiation time was markedly reduced to one third on treatment with the prepared formulation compared with control animals. The time required for complete hair growth was also reduced by 32%. Quantitative analysis of hair growth cycle after treatment with formulations and minoxidil (2%) exhibited greater number of hair follicles in anagenic phase compared with control. The results thus corroborate with the traditionally acclaimed hair growth-promoting capabilities of the plants. The prepared formulation also holds potential for treatment of alopecia.

Enzymatic hydrolysis of green tea seed extract and its activity on 5alpha-reductase inhibition

Two kaempferol glycosides were isolated from green tea seed extract (GTSE). After conducting a structure analysis, these two compounds were identified as kaempferol-3-O-[2-O-beta-D-galactopyranosyl-6-O-alpha-L-rhamnopyranosyl]-beta-D-glucopyranoside (compound 1) and kaempferol-3-O-[2-O-beta-D-xylopyranosyl-6-O-alpha-L-rhanmopyranosyl]-beta-D-glucopyranoside (compound 2). These two compounds were hydrolysed by o-glycolytic enzymes for the production of kaempferol. After performing several reactions, we found the optimum enzyme combination, a reaction with beta-galactosidase and hesperidinase. Finally, we produced kaempferol of above 95% purity. The 5alpha-reductase inhibition activities of GTSE hydrolysate (GTSE-H) containing kaempferol were evaluated by the contact cell-based metabolic method using a stable HEK 293 cell line. GTSE-H showed a good inhibition effect on HEK 293 cell lines both type 1 and type 2 on 5alpha-reductase. Especially, GTSE-H inhibited type 2 with kaempferol content dependency. The results indicate that the inhibition activity of hydrolysate on 5alpha-reductase type 2 increases in accordance with kaempferol content.