Inflammatory Acne

In Vitro Cytotoxicity and Antimicrobial Activity against Acne-Causing Bacteria and Phytochemical Analysis of Galangal (Alpinia galanga) and Bitter Ginger (Zingiber zerumbet) Extracts

Galangal (Alpinia galanga (L.) Willd) and bitter ginger (Zingiber zerumbet (L.) Roscoe) are aromatic rhizomatous plants that are typically used for culinary purposes. These rhizomatous plants have many biological properties and the potential to be beneficial for pharmaceutics. In this study, we evaluated the antioxidant and antimicrobial activities, with a specific focus on acne-causing bacteria, as well as the phytochemical constituents, of different parts of galangal and bitter ginger. The rhizomes, stems, and leaves of galangal and bitter ginger were separately dried for absolute ethanol and methanol extractions. The extracts were used to evaluate the antioxidant activity using a DPPH radical scavenging assay (0.005-5000 μg/mL), antimicrobial activity against acne-causing bacteria (0.50-31.68 mg/mL), and in vitro cytotoxicity toward human keratinocytes and fibroblasts (62.5-1000 μg/mL), as well as analyses of bioactive phytochemicals via GC-MS and LC-MS/MS (500 ppm). The ethanol and methanol extracts of bitter ginger and galangal's rhizomes (BRhE, BRhM, GRhE, and GRhM), stems (BStE, BStM, GRhE, and GRhM), and leaves (BLeE, BLeM, GLeE, and GLeM), respectively, showed antioxidant and antimicrobial activities. The extracts of all parts of bitter ginger and galangal were greatly antioxidative with 0.06-1.42 mg/mL for the IC50 values, while most of the extracts were strongly antimicrobial against C. acnes DMST 14916, particularly BRhM, BRhE, GRhM, and GRhE (MICs: 3.96-7.92 mg/mL). These rhizome extracts had also antimicrobial activities against S. aureus TISTR 746 (MICs: 7.92-31.68 mg/mL) and S. epidermidis TISTR 518 (MICs: 7.92-15.84 mg/mL). The extracts of bitter ginger and galangal rhizomes were not toxic to HaCaT and MRC-5 even at the highest concentrations. Through GC-MS and LC-MS/MS analysis, phytochemicals in bitter ginger rhizome extracts, including zerumbone, tectorigenin, piperic acid, demethoxycurcumin, and cirsimaritin, and galangal rhizome extracts, including sweroside and neobavaisoflavone, were expected to provide the antioxidant and anti-microbial activities. Therefore, the results suggest that the bitter ginger and galangal extracts could be natural anti-acne compounds with potential for pharmaceutic, cosmetic, and aesthetic applications.

Models in acnegenesis

Cosmetics and ointments utilized for dermatological purposes often bear unintended and sometimes opposing effects of their indicated use. Although there exists various animal and human models of acnegenesis, such as the Mexican hairless dog, the Rhino mouse, and the rabbit ear assay (REA), an elucidative assay that precisely reflects comedogenesis is not yet available. In this review, acnegenic components--i.e., keratinization, androgens, bacteria, sebum and genetics--are examined on an individual basis and correlated to animal models. Current animal models of comedogenesis focus on individual aspects of a multifaceted clinical condition, acne. Presently, the most commonly used assay is the REA, which possesses a hypersensitive response to acnegenic substances compared to human skin; however, this model is unable to accurately depict the acnegenic potential of chemical compounds, and is therefore only valuable for distinguishing absolute negatives. Developing an animal model that is true to the human condition will require further epidemiological evaluation of acne to elucidate the complex condition.

Current use of anti-infectives in dermatology

Dermatologic diseases encompass a broad category of pathologic situations. Infection remains a significant aspect of the pathology faced in patient encounters, and it is natural to expect that anti-infectives play a major element in the armamentarium utilized by dermatologists. Aside from the treatment of the classic bacterial and fungal infections, there are now new uses for antiviral agents to help suppress recurrent disease, such as herpes simplex. There is also the novel approach of using anti-infectives, or agents that have been thought to have antimicrobial activity, to treat inflammatory diseases. This review describes anti-infectives, beginning with common antibiotics used to treat bacterial infections. The discussion will then cover the current use of antivirals. Finally, the description of antifungals will be separated, starting with the oral agents and ending with the topical antimycotics. The use of anti-infectives in tropical dermatology has been purposefully left out, and perhaps should be the subject of a separate review. Cutaneous bacterial infections consist chiefly of those microorganisms that colonize the skin, such as species of staphylococcus and streptococcus. Propionibacterium acnes and certain other anaerobes can be involved in folliculitis, pyodermas and in chronic conditions such as hidradenitis suppurativa.

Topical antibacterial treatments for acne vulgaris : comparative review and guide to selection

Topical antibacterial agents are an essential part of the armamentarium for treating acne vulgaris. They are indicated for mild-to-moderate acne, and are a useful alternative for patients who cannot take systemic antibacterials. Topical antibacterials such as clindamycin, erythromycin, and tetracycline are bacteriostatic for Propionibacterium acnes, and have also been demonstrated to have anti-inflammatory activities through inhibition of lipase production by P. acnes, as well as inhibition of leukocyte chemotaxis. Benzoyl peroxide is a non-antibiotic antibacterial agent that is bactericidal against P. acnes and has the distinct advantage that thus far, no resistance has been detected against it. Combined agents such as erythromycin/zinc, erythromycin/tretinoin, erythromycin/isotretinoin, erythromycin/benzoyl peroxide, and clindamycin/benzoyl peroxide are increasingly being used and have been proven to be effective. They generally demonstrate good overall tolerability and are useful in reducing the development of antibacterial resistance in P. acnes. The selection of a topical antibacterial agent should be tailored for specific patients by choosing an agent that matches the patient's skin characteristics and acne type. Topical antibacterial agents should generally not be used for extended periods beyond 3 months, and topical antibacterials should ideally not be combined with systemic antibacterial therapy for acne; in particular, the use of topical and systemic antibacterials is to be avoided as far as possible.

Current concepts of the pathogenesis of acne: implications for drug treatment

The pathogenesis of acne is complex, with strong evidence supporting the involvement of sebaceous hyperplasia, follicular hyperkeratinisation, bacterial hypercolonisation, as well as immune reactions and inflammation. High sebum concentrations and follicular hyperkeratinisation lead to a change of the follicular milieu with consecutive proliferation of bacteria, chiefly Propionibacterium acnes. This leads to further increased production of the pro-inflammatory cytokines interleukin-1alpha and tumour necrosis factor alpha by T cells and keratinocytes, leading to proliferation of both cell types. Follicular keratinocytes fail to differentiate by apoptosis and produce hypergranulosis similar to the impermeable skin outer layer, resulting in the formation of microcomedones. Further inflammatory responses lead to the development of increasing degrees of severity in inflammatory forms of acne. Retinoids aid the differentiation and reduce the hyperproliferation of keratinocytes, and can inhibit the migration of leucocytes. Combination therapy using retinoids plus benzoyl peroxide or antibacterials can treat existing acne lesions faster than the individual agents alone and can also prevent the development of new lesions. The new retinoids (e.g. adapalene) have not only the typical potent comedolytic activity but also anti-inflammatory effects. When added to antibacterial therapy, topical retinoids demonstrate faster and significantly greater reduction of inflammatory acne lesions and comedones than antibacterials alone.

Antibacterial therapy for acne: a guide to selection and use of systemic agents

Acne vulgaris is a very common disorder, affecting virtually every adolescent at some point in time. Systemic antibacterials have been used in the treatment of acne for many years, and there are several commonly used antibacterials which have established efficacy and safety records. In recent years, the issue of antibacterials resistance has become more prominent, especially with concerns that Propionibacterium acnes can transfer antibacterials resistance to other bacteria within the resident skin flora. Commonly used antibacterials include tetracycline, doxycycline, minocycline, erythromycin (and other macrolides) and trimethoprim/sulfamethoxazole (cotrimoxazole). The choice of antibacterial should take into account efficacy, cost-effectiveness, benefit-risk ratios, patient acceptability and the potential for the development of resistance. Poor clinical response can be the result of poor compliance, inadequate duration of therapy, development of gram-negative folliculitis, resistance of P. acnes to the antibacterial(s) administered, or a high sebum excretion rate. In order to help prevent the development of resistance a number of measures should be undertaken: antibacterials are prescribed for an average of 6 months; if retreatment is required, utilize the same antibacterial; generally, antibacterials should be given for at least 2 months before considering switching due to poor therapeutic response; concomitant use of oral and topical chemically-dissimilar antibacterials should be avoided (try benzoyl peroxide and/or retinoids instead) and systemic isotretinoin should be considered if several antibacterials have been tried without success.

Current options for the topical treatment of acne vulgaris

The etiopathogenesis of acne vulgaris, a common disorder of youth and adolescence, includes four primary processes: hyperkeratinization (plugging) of the pilosebacous follicles, increased testosterone levels, bacterial colonization with Propionibacterium acnes, and inflammation. No single agent has yet been developed that addresses all of these factors. Combination regimens, therefore, which usually include an antibiotic and an agent to reduce follicular plugging, have become the mainstay of treatment. Despite a relative dearth of new treatments for almost a decade, recent research has produced a number of new significant oral and topical agents. Azelaic acid, a naturally occurring dicarboxylic acid analogue, has shown promise, and a group of retinoids that include adapalene, tazarotene, and reformulations of tretinoin represent new and forthcoming agents for topical treatment of acne vulgaris. Some studies indicate that several of these agents are associated with less skin irritation than previous formulations while they retain potent comedolytic activity. Adapalene also possesses significant anti-inflammatory activity.