Peptides with antimicrobial and anti-inflammatory activities that have therapeutic potential for treatment of acne vulgaris

The pathogenesis of acne vulgaris is multifactorial involving infection of the pilosebaceous unit with Propionibacterium acnes and a cytokine-mediated inflammatory response. Five frog skin-derived antimicrobial peptides ([D4k]ascaphin-8, [G4K]XT-7, [T5k]temporin-DRa, brevinin-2GU, and B2RP-ERa), chosen for their low hemolytic activity against human erythrocytes, were assessed for their effects on the growth of clinical isolates of P. acnes and on the release of pro-inflammatory and anti-inflammatory cytokines from peripheral blood mononuclear (PBM) cells. All peptides inhibited the growth of P. acnes with the highest potency exhibited by [D4k]ascaphin-8 (minimum inhibitory concentration, MIC=3-12.5 μM). Release of TNF-α from concanavalin A (ConA)-stimulated PBM cells was significantly reduced by [D4k]ascaphin-8, [G4K]XT-7, brevinin-2GU, and B2RP-ERa (1 and 20 μg/ml) and by [T5k]temporin-DRa (20 μg/ml). Release of IFN-γ from unstimulated PBM cells was significantly reduced by [D4k]ascaphin-8 and brevinin-2GU (1 and 20 μg/ml). No peptide showed significant effects on Il-17 release. Release of the anti-inflammatory cytokines TGF-β, IL-4, and IL-10 from both unstimulated and ConA-treated PBM cells was significantly increased by [T5k]temporin-DRa and B2RP-ERa (1 and 20μg/ml). The potent activities of [D4k]ascaphin-8 and [T5k]temporin-DRa in inhibiting the growth of P. acnes and the release of pro-inflammatory cytokines, and in stimulating the release of anti-inflammatory cytokines suggest a possible therapeutic role in the treatment of acne vulgaris.

Eradication of Propionibacterium acnes biofilms by plant extracts and putative identification of icariin, resveratrol and salidroside as active compounds

Propionibacterium acnes is a Gram-positive bacterium that plays an important role in the pathogenesis of acne vulgaris. This organism is capable of biofilm formation and the decreased antimicrobial susceptibility of biofilm-associated cells may hamper efficient treatment. In addition, the prolonged use of systemic antibiotic therapy is likely to lead to the development and spread of antimicrobial resistance. In the present study we investigated whether P. acnes biofilms could be eradicated by plant extracts or their active compounds, and whether other mechanisms besides killing of biofilm cells could be involved. Out of 119 plant extracts investigated, we identified five with potent antibiofilm activity against P. acnes (extracts from Epimedium brevicornum, Malus pumila, Polygonum cuspidatum, Rhodiola crenulata and Dolichos lablab). We subsequently identified icariin, resveratrol and salidroside as active compounds in three of these extracts. Extracts from E. brevicornum and P. cuspidatum, as well as their active compounds (icariin and resveratrol, respectively) showed marked antibiofilm activity when used in subinhibitory concentrations, indicating that killing of microbial cells is not their only mode of action.

Antimicrobial efficacy of metapex (calcium hydroxide with iodoform formulation) at different concentrations against selected microorganisms--an in vitro study

The objective of this study was to assess, in vitro, the effectiveness of several concentrations of Metapex (0.22 gm/ml, 0.022 gm/ml, 0.0022 gm/ml) in the elimination of selected microorganisms. Different concentrations of Metapex were prepared by dissolving it in ethanol (99.9%) Pre-sterilized Whatman paper discs, 6 mm in diameter and soaked with the test solution, were prepared and placed onto the previously seeded agar Petri plates. Plates were incubated aerobically for Enterococcus faecalis (E. Faecalis) and Candida albicans (C. albicans), anaerobically for Bacteroid fragilis (B. fragilis) and Propionibacterium acne respectivally. A zone of inhibition was recorded for each plate and the results were analysed statistically. There was significant reduction in the size of zone of inhibition against P. acne, as the concentration of metapex decreases. At lower concentrations of metapex there was no zone of inhibition observed against E. Faecalis, C. Albicans and B. Fragilis. The result of this study suggested that Metapex is a potent antimicrobial agent at higher concentration.

Anti-inflammatory effects of active constituents extracted from Chinese medicinal herbs against Propionibacterium acnes

Interleukin-8 (IL-8) and tumour necrosis factor-alpha (TNF-α) from keratinocyte play important roles in initiating the inflammatory process of acne. They are used as major elements to evaluate the anti-inflammatory activity of drugs. In this study, various active constituents extracted from Chinese medicinal herbs were tested for their anti-inflammatory effects against P. acnes using ELISA. Among the constituents, matrine, baicalin, ursolic acid, sodium danshensu, magnolol, honokiol, hesperidin and andrographolide significantly reduced IL-8 and TNF-α by human HaCaT keratinocyte cells pretreated with heat-killed P. acnes. Excepting hesperidin, these active constituents presented dose-dependent inhibitory effects. Our studies showed that all of them exhibited low cytotoxicity at 5 µg mL⁻¹ in tested cell lines, and even at 50 µg mL⁻¹, in the cases of matrine, baicalin, ursolic acid and sodium danshensu. Based on the obtained results, it can be suggested that these active constituents are potential acne-mitigating candidates for cosmetic applications.

Pharmacological properties of Myrtacine® and its potential value in acne treatment

This study aimed at evaluating the antiproliferative, antibacterial, and anti-inflammatory properties of an ethanolic myrtle extract (Myrtacine®) in vitro, characterising its potential active compounds (myrtucommulones A and B') by structural analysis, and evaluating their biological activity. Antiproliferative activity was assessed by the BrdU incorporation assay in HaCat keratinocytes and inhibitory and bactericidal activities against P. ACNES strains by measuring the minimal inhibitory concentration (MIC) and D value. Anti-inflammatory effect was evaluated by measuring 6-keto-prostaglandin F1 α and [³H]-arachidonic acid metabolite production in keratinocytes stimulated for inflammation. Myrtacine® inhibited keratinocyte proliferation by 27 % and 76 % at 1 and 3 µg/mL, respectively (p < 0.001). A comparable effect, though less marked, was observed with 5 µg/mL myrtucommulones A and B' (-36 % and -28 %, respectively). Myrtacine® inhibited erythromycin-sensible and -resistant P. ACNES strains growth with MICs of 4.9 µg/mL and 2.4 µg/mL, respectively. Myrtucommulone B' and myrtucommulone A displayed a similar inhibitory activity against both strains (for both strains, MIC = 1.2 µg/mL and about 0.5 µg/mL, respectively). At 3 and 10 µg/mL, Myrtacine® significantly decreased all metabolite production from cyclooxygenase (81 % and 107 %, p < 0.0001) and lipoxygenase (52 % and 95 %, p < 0.001) pathways. Finally, Myrtacine® exhibited a concentration-dependent anti-lipase activity at 100 µg/mL and 1 mg/mL, as it decreased lipase activity by respectively 53 % and 100 % (p < 0.01 for both). In conclusion, in vitro, Myrtacine® demonstrated antiproliferative, antibacterial, and anti-inflammatory properties that may be of value to exert a global action in the treatment of acne lesions.

Antibacterial properties of a glycolipid-rich extract and active principle from Nunavik collections of the macroalgae Fucus evanescens C. Agardh (Fucaceae)

This study investigated the antibacterial activity of glycolipid-rich extracts of the brown macroalga Fucus evanescens in cell culture. Accessions were collected on the Arctic coast of Ungava Bay, Nunavik, Quebec. The crude ethyl acetate extract of these accessions showed strong antibacterial activity (≥4 log(10) cfu) against Hemophilus influenzae , Legionella pneumophila , Propionibacterium acnes (ATCC and clinical isolate), and Streptococcus pyogenes at 100 µg/mL. This algal extract inhibited by 3 log(10) Clostridium difficile and methicillin-resistant Staphylococcus aureus , whereas Bacillus cereus , Escherichia coli , Klebsiella pneumoniae , and Pseudomonas aeruginosa were not significantly affected. Further investigations of the activity of a glycolipid-rich fraction, extracted with dichloromethane, against Propionibacterium acnes showed an MIC(100) of 50 µg/mL, with an inhibition of more than 99% at only 7.8 µg/mL. The main active compound, a β-d-galactosyl O-linked glycolipid, was synthesized for the bioassay and showed an MIC(100) of 50 µg/mL but lost its activity more quickly with only 50% of inhibition at 12.5 µg/mL. Therefore, the semipurified F. evanescens extract could be a good choice for future research into the development of alternative treatments for acne therapy.

Tyrosinase activity of Greyia flanaganii (Bolus) constituents

Hyper-pigmentation of the skin is a common problem that is prevalent in middle aged and elderly people. It is caused by over production of melanin. Tyrosinase is known to be the key enzyme in melanin production. Ethanolic extract of Greyia flanaganii leaves showed significant (P<0.05) antityrosinase activity exhibiting the IC₅₀ of 32.62 μg/ml. The total extract was further investigated for its toxicity and effect on melanin production by melanocytes cells, and showed significant inhibition (P<0.05) (20%) of melanin production at 6.25 μg/ml and low levels of cytotoxicity (IC₅₀<400 μg/ml). The amount of antioxidants necessary to decrease the initial DPPH absorbance by 50% (EC₅₀) by the total ethanolic extract was found to be 22.01 μg/ml. The effect of G. flanaganii against acne causing bacteria, Propionibacterium acnes, was investigated using microdilution assay. The MIC of the extract of G. flanaganii was found to be 250 μg/ml. Bioassay-guided fractionation led to the isolation of (3S)-4-hydroxyphenethyl 3-hydroxy-5-phenylpentanoate (1), 2',4',6'-trihydroxydihydrochalcone (2), 2',6',4-trihydroxy-4'-methoxydihydrochalcone (3), 2',6'-dihydroxy-4'-methoxydihydrochalcone (4), 5,7-dihydroxyflavanone [(2S)-pinocembrin] (5), 2',6'-dihydroxy-4',4-dimethoxy dihydrochalcone (6) and (2R,3R)-3,5,7-trihydroxy-3-O-acetylflavanone (7). The isolated compounds were tested for their antioxidant, cytotoxicity, tyrosinase inhibition and antibacterial activities. Compound 2 exhibited significant (P<0.05) antityrosinase activity exhibiting the IC₅₀ of 69.15 μM. The isolated compounds showed low toxicity of the cells with reduction of melanin content of the cells. All compounds tested showed good radical scavenging activity. These data indicates that G. flanaganii extract and its isolated phenolic constituents could be possible skin lightening agents.

Neolitsea aciculata essential oil inhibits drug-resistant skin pathogen growth and Propionibacterium acnes-induced inflammatory effects of human monocyte leukemia

This study examined the chemical composition of Neolitsea aciculata essential oil (NAE) and its biological activities. NAE was obtained by hydro-distillation of N. aciculata leaves collected in Jeju Island and analyzed by gas chromatography equipped with a mass spectrometer detector. 1-Dodecen-3-yne (12.5%), calarene (11.5%) and elemol (9.5%) were identified as the major components of NAE. The antibacterial and anti-inflammatory activities of NAE against skin pathogens were examined to determine the protective properties against acne vulgaris. NAE exhibited moderate to strong antibacterial activity against drug-susceptible and -resistant Propionibacterium acnes and Staphylococcus epidermidis, which are known as acne-causing bacteria. In addition, NAE reduced the P. acnes-induced secretion of tumor necrosis factor-alpha (TNF-alpha) and interleukin-8 (IL-8) in THP-1 cells, highlighting its anti-inflammatory effects. The DPPH radical scavenging activities of NAE also revealed moderate antioxidant properties (IC50, 21.3 microL/mL). Overall, NAE is an attractive candidate as an ingredient in skin care products.

Cathelicidin-BF, a snake cathelicidin-derived antimicrobial peptide, could be an excellent therapeutic agent for acne vulgaris

Cathelicidins are a family of antimicrobial peptides acting as multifunctional effector molecules in innate immunity. Cathelicidin-BF has been purified from the snake venoms of Bungarus fasciatus and it is the first identified cathelicidin antimicrobial peptide in reptiles. In this study, cathelicidin-BF was found exerting strong antibacterial activities against Propionibacterium acnes. Its minimal inhibitory concentration against two strains of P. acnes was 4.7 µg/ml. Cathelicidin-BF also effectively killed other microorganisms including Staphylococcus epidermidis, which was possible pathogen for acne vulgaris. Cathelicidin-BF significantly inhibited pro-inflammatory factors secretion in human monocytic cells and P. acnes-induced O₂^.− production of human HaCaT keratinocyte cells. Observed by scanning electron microscopy, the surfaces of the treated pathogens underwent obvious morphological changes compared with the untreated controls, suggesting that this antimicrobial peptide exerts its action by disrupting membranes of microorganisms. The efficacy of cathelicidin-BF gel topical administering was evaluated in experimental mice skin colonization model. In vivo anti-inflammatory effects of cathelicidin-BF were confirmed by relieving P. acnes-induced mice ear swelling and granulomatous inflammation. The anti-inflammatory effects combined with potent antimicrobial activities and O₂^.− production inhibition activities of cathelicidin-BF indicate its potential as a novel therapeutic option for acne vulgaris.

New, relevant information and innovative interventions in the management of acne

The recent innovative interventions in the acnes (acne vulgaris, acne rosacea and acne inversa) have not occurred in their management; rather the major changes are occurring in how the disorders and the individual lesions are seen to originate and develop. To finalize the optimal management of each of the acnes will ultimately require that every step in the aetiopathogenesis described and postulated here will need to be tested, validated, and then appropriately countered with environmental and lifestyle adjustments that will lead ultimately to prevention of 'the blight of youth' and its variants.

[Postoperative recurrence of subdural empyema]

We present a case of recurrent subdural post-surgical empyema by Proprionibacterium acnes after a first drained empyema in which no microbiological diagnosis was reached. P. acnes is a gram-positive anaerobic organism which is part of the saprophytic flora of the skin and others parts of the body. However, it can cause infections, as in the central nervous system, especially post-surgical infections in which can be the second more frequent organism after Staphylococcus aureus. P. acnes grows slowly and shows better growth in liquid anaerobic media. It is usually resistant to metronidazol and sensitive to penicillin. In postoperative central nervous system infections we must take into account the possibility of this organism, process the sample properly and keep touch with the Microbiology Department.

In vitro antibacterial and anti-inflammatory properties of seaweed extracts against acne inducing bacteria, Propionibacterium acnes

This study was conducted to evaluate the antimicrobial activities of common seaweeds from the coast of South Korea against the etiologic agents of acne vulgaris. Fifty-seven species of seaweed were screened for potential antimicrobial activity. Methanol extracts of 13 species (22.8%) showed inhibitory effects against Propionibacterium acnes. The aqueous extracts of only two species (3.5%) showed antimicrobial activity. When tested with the agar disk diffusion method, Ecklonia cava, E. kurome, Ishige sinicola, and Symphyocladia latiuscula had the strongest inhibitory effects. However, these four seaweed extracts showed no antibacterial activity against Staphylococcus epidermidis at 5 mg disk-1. The minimum inhibitory concentration (MIC) values of E. cava and E. kurome were both 0.31 mg ml-1 and the MIC values of l. sinicola and S. latiuscula were 0.26 and 0.21 mg ml-1, respectively. Among whole plants of E. cava and E. kurome, extracts of the pinnate blade had the highest inhibitory activity on bacterial growth. In cytotoxicity assays, methanol extracts of E. cava, E. kurome, and I. sinicola showed no effect on cell viability at concentrations of 200 microg ml-1. However, the methanol extracts of S. latiuscula reduced cell viability rates to 50% at the same concentration. Additionally, methanol extracts of E. cava, E. kurome, and I. sinicola potently inhibited the in vitro production of nitric oxide. These results suggest that the methanol extracts from these three species may be useful in the development of therapeutic agents for acne vulgaris. Further investigations to determine the bioactive compound are in progress.

Preparation, characterization, and in vitro antimicrobial assessment of nanocarrier based formulation of nadifloxacin for acne treatment

The objective of the present study was to develop a nanocarrier based formulation of nadifloxacin and to investigate its in vitro antimicrobial effect against Propionibacterium acnes. Nanocarrier based microemulsion formulations were prepared by aqueous titration method, using oleic acid as oil phase, Tween-80 as surfactant and ethanol as co-surfactant in different ratios. This procedure yielded monodisperse microemulsions exhibiting a mean droplet size in the range of 95-560 nm. This range of particle size is good to treat follicle related disorders like acne vulgaris because the size of follicles is in the range of 50-100 microm. Furthermore the optimized formulations were characterized for surface morphology by transmission electron microscopy and refractive index. The permeation studies were carried out using rat skin mounted in Franz diffusion cells. Flux of the optimised formulation was 2.24 times that of control. The diameter of inhibition zone of the microemulsion was found good but smaller than that of a clindamycin disc because of the higher therapeutic efficacy of clindamycin against P. acnes. The results indicated that the developed microemulsion shows promising results against P. acnes bacteria and may be a good approach for acne treatment.

The development of antimicrobial resistance due to the antibiotic treatment of acne vulgaris: a review

OBJECTIVE

To review recent studies on the use of antibiotics in acne vulgaris which provide insight into the development of antimicrobial resistance.

DATA SOURCES

Sources for this article were identified by searching the English literature by Medline for the period 1960 to March 2009.

STUDY SELECTION

The following relevant terms were used: acne, acne vulgaris, acne and antibiotic therapy, acne and antimicrobial resistance, acne and resistance mechanisms, acne and systemic infections, acne and antibiotic resistance and coagulase-negative Staphylococcus aureus (S. aureus), acne and antibiotic resistance and upper respiratory infection.

DATA SYNTHESIS

Both correct and incorrect use of antibiotics for acne vulgaris can promote antimicrobial resistance. The development of this resistance is promoted by several factors, including antibiotic monotherapy, long-term administration of antibiotics, indiscriminate use outside their strict indications, dosing below the recommended levels, and the administration of antibiotics without concurrent benzoyl peroxide and/or topical retinoids.

CONCLUSION

Long-term use of antibiotics in the treatment of acne vulgaris can lead to antimicrobial resistance with serious and intractable problems not limited to Propionibacterium acnes (P. acnes), the skin and acne vulgaris themselves, but also to other bacterial species, with systemic consequences. These findings suggest that antibiotics should be prescribed in combination with benzoyl peroxide and/or topical retinoids and be limited to a maximum of several months.

Efficacy of benzoyl peroxide (5.3%) emollient foam and benzoyl peroxide (8%) wash in reducing Propionibacterium acnes on the back

BACKGROUND

Topical treatment of acne vulgaris on the back is challenging largely due to the extensive broad surface with difficult to reach areas. A "leave-on" foam is suited for application to the trunk due to ease of application and spreadability. Prior to this trial, no data on Propionibacterium acnes (P. acnes) reduction on the back has existed for any benzoyl peroxide (BP) formulations or other acne treatments.

OBJECTIVES

To evaluate the effectiveness of BP (5.3%) emollient foam and BP (8%) wash in reducing P. acnes levels on the back.

METHODS

Five-week open-label single-center study of 20 healthy subjects (> 18 years old), colonized with P. acnes on their backs (> 10,000 colonies per cm2). Subjects were treated once daily with BP (5.3%) foam for two weeks; no treatment in week 3, and BP (8%) wash once daily for two further weeks. Quantitative bacteriologic cultures obtained at baseline and weeks 1, 2, 3, 5 and 6.

RESULTS

Nineteen evaluable patients. Total P. acnes counts were reduced by 1.9 log (one week) and 2.1 log (two weeks) with BP (5.3%) emollient foam. BP (8%) wash did not reduce P. acnes counts after two weeks.

DISCUSSION

BP (5.3%) emollient foam was superior to BP (8%) wash in reducing P. acnes on the back. The lack of effect of BP (8%) wash is surprising in view of the demonstrated results on the face and warrants further study.

Trends in the treatment of acne vulgaris: are measures being taken to avoid antimicrobial resistance?

BACKGROUND

Acne vulgaris has been treated with long-term courses of antibiotics since the 1960s. Antibiotic-resistance of Propionibacterium acnes (P. acnes) was first documented in the late 1970s, and, over 20 years later, the problem of antibiotic resistance still exists.

PURPOSE

The aim of this study was to assess trends in prescribing antibiotics for acne from 1997-2006.

METHODS

The authors examined the National Ambulatory Medical Care Survey (NAMCS) database and recorded medications at all visits to the physician in which acne vulgaris (ICD-9-CM code 706.1) was the only diagnosis from 1997-2006.

RESULTS

Declines in the use of erythromycin and isotretinoin (both P < 0.001) for acne were noted for all physicians. Tetracyclines saw significant increases in use by both dermatologists and non-dermatologists (P < 0.01 and P = 0.05, respectively). Prescribing of benzoyl peroxide monotherapy was unchanged for non-dermatologists (P = 0.22) and is on the decline for dermatologists (P < 0.001). The use of BPO + clindamycin combination topical treatments rose sharply for all physicians (P < 0.001), resulting in greater use of both total BPO and total clindamycin for acne over time (P < 0.001). Topical retinoid use increased among dermatologists (P < 0.05) but appeared to be on the decline among non-dermatologists (P = 0.067).

CONCLUSION

The development of antibiotic resistance is of concern. Greater awareness of retinoid use for maintenance therapy, using topical benzoyl peroxide to prevent resistance, and limiting use of oral antibiotics to as short a time period as possible are measures to contribute to better eco-responsible acne treatment.

Activities of ten essential oils towards Propionibacterium acnes and PC-3, A-549 and MCF-7 cancer cells

Ten essential oils, namely, mint (Mentha spicata L., Lamiaceae), ginger (Zingiber officinale Rosc., Zingiberaceae), lemon (Citrus limon Burm.f., Rutaceae), grapefruit (Citrus paradisi Macf., Rutaceae), jasmine (Jasminum grandiflora L., Oleaceae), lavender (Mill., Lamiaceae), chamomile (Matricaria chamomilla L., Compositae), thyme (Thymus vulgaris L., Lamiaceae), rose (Rosa damascena Mill., Rosaceae) and cinnamon (Cinnamomum zeylanicum N. Lauraceae) were tested for their antibacterial activities towards Propionibacterium acnes and in vitro toxicology against three human cancer cell lines. Thyme, cinnamon and rose essential oils exhibited the best antibacterial activities towards P. acnes, with inhibition diameters of 40 ± 1.2 mm, 33.5 ± 1.5 mm and 16.5 ± 0.7 mm, and minimal inhibitory concentrations of 0.016% (v/v), 0.016% (v/v) and 0.031% (v/v), respectively. Time-kill dynamic procedures showed that thyme, cinnamon, rose, and lavender essential oils exhibited the strongest bactericidal activities at a concentration of 0.25% (v/v), and P. acnes was completely killed after 5 min. The thyme essential oil exhibited the strongest cytotoxicity towards three human cancer cells. Its inhibition concentration 50% (IC₅₀) values on PC-3, A549 and MCF-7 tumor cell lines were 0.010% (v/v), 0.011% (v/v) and 0.030% (v/v), respectively. The cytotoxicity of 10 essential oils on human prostate carcinoma cell (PC-3) was significantly stronger than on human lung carcinoma (A549) and human breast cancer (MCF-7) cell lines.

Inhibitory effects of Fortunella japonica var. margarita and Citrus sunki essential oils on nitric oxide production and skin pathogens

A number of essential oils from citrus peels are claimed to have biological activities. Citrus peel, called 'Jin-Pi', is used in traditional medicine for digestion, severe cold, and fever. However, the antibacterial activities against skin pathogens and anti-inflammatory effects of the essential oils of Citrus sunki (JinGyul) and Fortunella japonica var. margarita (GumGyul) have not yet been described. Therefore, in this study, the essential oils of the citrus species C. sunki (CSE) and F. japonica var. margarita (FJE), both native to the island of Jeju, Korea, were examined for their anti-inflammatory and antimicrobial activities against skin pathogens. Four human skin pathogenic microorganisms, Staphylococcus epidermidis CCARM 3709, Propionibacterium acnes CCARM 0081, Malassezia furfur KCCM 12679, and Candida albicans KCCM 11282, were studied. CSE and FJE exhibited strong antimicrobial activity against most of the pathogenic bacteria and yeast strains that were tested. Interestingly, CSE and FJE even showed antimicrobial activity against antibiotic-resistant S. epidermidis CCARM 3710, S. epidermidis CCARM 3711, P. acnes CCARM9009, and P. acnes CCARM9010 strains. In addition, CSE and FJE reduced the lipopolysaccharide (LPS)-induced secretion of nitric oxide (NO) in RAW 264.7 cells, indicating that they have anti-inflammatory effects. We also analysed the chemical composition of the oils by gas chromatography-mass spectrometry (GC-MS) and identified several major components, including dl-limonene (68.18%) and beta-myrcene (4.36%) for CSE, and dl-limonene (61.58%) and carvone (6.36%) for FJE. Taken together, these findings indicate that CSE and FJE have great potential to be used in human skin health applications.

Free radical scavenging and anti-acne activities of mangosteen fruit rind extracts prepared by different extraction methods

The ethanol extracts of mangosteen fruit rinds prepared by several extraction methods were examined for their contents of bioactive compounds, DPPH-scavenging activity, and anti-acne producing bacteria against Propionibacterium acnes and Staphylococcus epidermidis. The dried powder of the fruit rind was extracted with 95% ethanol by maceration, percolation, Soxhlet extraction, ultrasonic extraction, and extraction using a magnetic stirrer. Soxhlet extraction promoted the maximum contents of crude extract (26.60% dry weight) and alpha-mangostin (13.51%, w/w of crude extract), and also gave the highest anti-acne activity with MIC 7.81 and 15.63 microg/mL and MBC 15.53 and 31.25 microg/mL against P. acnes and S. epidermidis, respectively. Ethanol 70% and 50% (v/v) were also compared in Soxhlet extraction. Ethanol 50% promoted the extract with maximum amounts of total phenolic compounds (26.96 g gallic acid equivalents/100 g extract) and total tannins (46.83 g tannic acid equivalents/100 g extract), and also exhibited the most effective DPPH-scavenging activity (EC(50) 12.84 microg/mL). Considering various factors involved in the process, Soxhlet extraction carried a low cost in terms of reagents and extraction time. It appears to be the recommended extraction method for mangosteen fruit rind. Ethanol 50% should be the appropriate solvent for extracting free radical-scavenging components, phenolic compounds, and tannins, while 95% ethanol is recommended for extraction of alpha-mangostin, a major anti-acne component from this plant.

Anti-acne-inducing bacterial activity of mangosteen fruit rind extracts

OBJECTIVE

The aims of this study were to determine the most effective solvent extract of mangosteen, anti-acne- inducing bacterial activity and the amount of alpha-mangostin, a major active component in each mangosteen fruit rind extract, using high-performance liquid chromatography (HPLC).

MATERIALS AND METHODS

The fruit rinds of mangosteen were extracted with hexane, dichloromethane, ethanol and water. The extracts were tested for antibacterial activity against bacteria that induce acne, including Propionibacterium acnes and Staphylococcus epidermidis. Thin-layer chromatographic autobiography against these bacteria was also performed for each extract, while the alpha-mangostin content was analyzed using a validated HPLC method.

RESULTS

The dichloromethane extract exhibited the strongest antibacterial effect with minimum inhibitory concentration values for both bacterial species at 3.91 microg/ml, while the minimum bactericidal concentration values against P. acnes and S. epidermidis were 3.91 and 15.63 microg/ml, respectively. Thin-layer chromatographic autobiography indicated that alpha-mangostin was present in all extracts, except the water extract, and is a major active component against both P. acnes and S. epidermidis. Using HPLC, the dichloromethane extract yielded the highest content (46.21% w/w) of alpha-mangostin followed by the ethanol extract (18.03% w/w), the hexane extract (17.21% w/w) and the water extract (0.54% w/w).

CONCLUSIONS

Dichloromethane extract exhibited the strongest anti-acne-inducing bacterial effect and this extract yielded the highest amount of alpha-mangostin.

Evaluation of the antibacterial activity of rhapontigenin produced from rhapontin by biotransformation against Propionibacterium acnes

Biotransformation is often used to improve chemical activity. We evaluated the antimicrobial activity of rhapontigenin, converted from rhapontin after treatment with Pectinex. Rhapontigenin showed 4-16 times higher antimicrobial activity than rhapontin. Activity was higher against Gram positive strains than Gram negative strains. Minimum inhibitory concentrations (MICs) of rhapontigenin, retinol, and five antibiotics were determined by microbroth dilution method for antibiotic-sensitive and -resistant Propionibacterium acnes. We also investigated the in vitro antibacterial activity of rhapontigenin in combination with antibiotic against antibiotic-resistant P. acnes. The antibiotic combination effect against resistant P. acnes was studied by checkerboard method. The combination formulations (rhapontigenin and clindamycin, retinol and clindamycin) showed synergic effects on the inhibition of the growth of clindamycin-resistant P. acnes. It is predictable that the combination of antibiotics with rhapontigenin is helpful to treat acne caused by antibiotic resistant P. acnes. The antibacterial activity of rhapontigenin was enhanced by biotransformation.

Comparative efficacy and safety results of two topical combination acne regimens

Combination therapy has become the standard for the management of acne, particularly for moderate-to-severe cases. Among these combinations, those regimens containing benzoyl peroxide (BPO), clindamycin and a retinoid have been used frequently as they address most aspects of acne pathogenesis. This study compares the efficacy and safety of two common topical treatment regimens in the treatment of a moderate to severe facial acne vulgaris: fixed-combination gel containing BPO 5% and clindamycin 1% (BPO/C) plus tretinoin microsphere gel 0.04% (RAM) versus a regimen of a fixed-combination gel containing clindamycin phosphate 1.2% and tretinoin 0.025% (CPT) plus a once-daily BPO 5% wash. While both regimens were safe and effective, regimen BPO/C+RAM yielded a more rapid onset of effect versus regimen CPT+BPO against both non-inflammatory and inflammatory lesions. Both treatment regimens were well-tolerated.

Advancement in benzoyl peroxide-based acne treatment: methods to increase both efficacy and tolerability

BACKGROUND

Antibiotic resistance of Propionibacterium acnes (P. acnes) is a growing phenomenon in the wake of widespread use of topical and systemic antibiotics for acne vulgaris. Benzoyl peroxide has a proven track record of safety and efficacy, and can decrease reliance on antibiotics in the treatment of acne.

PURPOSE

To review the literature for methods to increase the efficacy and tolerability of benzoyl peroxide (BPO).

METHODS

A PubMed literature search was done using the terms "benzoyl peroxide," "vehicle," "mechanism," and "delivery system." Relevant papers were reviewed for methods of increasing BPO efficacy and tolerability.

RESULTS

BPO in concentrations of 2.5%, 5% and 10% are equally effective at treating inflammatory acne. However, higher concentrations are associated with more adverse effects. The efficacy of BPO may be enhanced by the presence of Vitamin E and tertiary amines. BPO is also more efficacious if used in combination with topical retinoids than as a monotherapy. Novel vehicles including a microparticle delivery system and those with a hydrophase or urea base increase the tolerability of BPO without sacrificing efficacy.

CONCLUSION

Benzoyl peroxide has a proven track record of safety and efficacy for the treatment of acne. Recent discoveries have provided new methods of increasing the efficacy and tolerability of topical BPO, making it useful as monotherapy for mild acne or as an adjunct in the treatment of moderate to severe acne vulgaris.