HERBAL PLANTS AND PROPIONIBACTERIUM ACNES: AN OVERVIEW

Propionibacterium acnes are gram-positive anaerobic microorganism, which have been most recognized as a key factor for the development of acne. Acne is the most common skin disease and Propionibacterium acnes have been recognized as pus-forming bacteria triggering an inflammation in acne. Acne vulgaris is a chronic inflammatory disease of the pilosebaceous follicle, characterized by comedones, papules, pustules, cysts, nodules and often scars in certain sites of predilection, namely, the face, neck, upper trunk and arms. The present compiled work was conducted to make an overview and correlation between antimicrobial activities of medicinal plants against these etiologic agents of acne vulgaris. Different parts of various medicinal plants belongs to families like Liliaceae, Rutaceae, Zingiberaceae, Myrtaceae, Lamiaceae, etc. contains alkaloids, tannins, flavonoids, terpenoids, volatile oil and essential oil which are reported with significant effect against this bacteria.


INTRODUCTION 1.1
Acne :Acne vulgaris is a chronic inflammatory disease of the pilosebaceous follicle, characterized by comedones, papules, pustules, cysts, nodules and often scars in certain sites of predilection, namely, the face, neck, upper trunk and arms. 1 Propionibacterium acnes release pro-inflammatory cytokines as well as antigens and mitogen(s), with cellular and non-cellular responses to these products triggering inflammation. 2 Acne vulgaris is a common skin disease that involves individuals of all ages. It has been estimated to affect 79% to 95% of the adolescent population, 40% to 54% of individuals older than 25 years, and 12% of women and 3% of men in their mid ages. 3 Acne is genetic and if it runs in family, three out of four children may have it, because it is genetic problem brought on by hormones. 4 The major hormones involved in the etiology of acne are androgens, taking into account that 5 α-reductase type 1, responsible for the conversion of testosterone into dehydrotestosterone (DHT), appears to be most prevalent in the sebaceous glands of isolated acne areas and to have greater activity in women with moderate to severe acne. 5,6,7 Acne is a group of disorders that causes outbreaks of skin lesions commonly called pimples factors which contribute to the development of acne include hormonal imbalance, bacterial infection, stress, food, or cosmetic application additionally some species of Propionibacterium are found in milk and cheese and some time in other agricultural product. 8 Propionibacterium acnes are a gram positive microaerophilic bacteria which are responsible for the local inflammatory response of acne, with the activation of monocytes and production of cytokines. 5,9 It is caused by the oil glands present in the skin making too much sebum, an oily substance, which leads to plugged pores. It is the most common skin disease. Propionibacterium acnes are a common contaminant found in blood and CSF (cerebrospinal fluid) culture. 10 Although acne is not a serious health threat, severe acne can lead to disfiguring and permanent scarring. For many years antibiotics and hormones were usually applied to treat acne. However, these agents are often accompanied by severe side effects and drug resistance. 11 Acne shows up in the form of filthy lesions like blackheads, whiteheads, inflammatory lumps or boils such as pustules, papules, cysts, and nodules. Propionibacterium acnes are found briefly on the skin of neonates, but true colonization begins during the 1-3 years prior to sexual maturity due to hormonal imbalance. 12 Factors promoting the development of acne are: increased sebum production, ductal cornification, hyperkeratinization, bacterial colonization of the pilosebaceus ducts and inflammation. 2 1.2 Types of Acne : Acne could be classified into five categories: acne vulgaris, acne rosacea, acne conglobata, acne fulminans, and pyroderma faciale. Among these acne vulgaris is the most common and mild type of acne. 1.2.1 Acne Vulgaris: Acne vulgaris is the most common cutaneous chronic inflammatory disorder of multifactorial origin with prevalence in adolescents. It consists of the pilosebaceous follicles characterized by comedones, papules, pustules, nodules, cysts and often scars in certain sites of predilection, namely the face, neck, chest, arms and back. Acne vulgaris is common among 95% and 83% of teenage boys and girls, respectively, and affects 85%, 8% and 3% of people aged between 12-25, 25-34 and 35-44 years, respectively. 13 It is further classified as 14 : 1.2.1.1. Papules: Slightly larger, tender, and red or pink blemishes which are most often found to be inflamed are called papules. This type of acne is potentially risky to be picked or popped since they can turn into larger and painful cysts with some possibility of scarring. 1.2.1.2. Macule-A macule is a temporary red, or red-pink, spot that is left after the acne has healed. This has a well-defined border and may stay for many days before disappearing. Nodules are larger and more deep seated than pustules. These lesions are characterized by painful, firm, and solid lumps filled with pus. 1.2.1.5. Cysts: Acne cysts or cystic acne is the most severe and persistent type of acne. These large inflamed lesions are oftentimes playing as the most influential threat behind acne scar. More often than not, it is found that cystic acne is the outcome of popping or squeezing pus filled and inflamed smaller comedones. 1.2.2. Acne rosacea: Rosacea is a common skin disorder affecting middleaged and older adults. Many patients mistakenly assume that early rosacea is normally a sign of aging skin and are not aware of effective treatments that exist to prevent progression to permanent disfiguring skin changes.
It mainly affectsmiddle-aged and older adults and found in cheeks, nose, chin, and forehead. 15 1.2.3. Acne conglobata: Acne conglobata is an uncommon and unusually severe form of acne characterized by burrowing and interconnecting abscesses and irregular scars (both keloidal and atrophic), often producing pronounced disfigurement. The comedones often occur in a group of 2 or 3, and cysts contain foul-smelling seropurulent material that returns after drainage. The nodules are usually found on the chest, the shoulders, the back, the buttocks, the upper arms, the thighs, and the face. 16 Acne conglobata may develop as a result of a sudden deterioration of existing active papular or pustular acne, or it may occur as the recrudescence of acne that has been quiescent for many years. 17 1.2.4. Acne fulminans: It is an uncommon form of ulcerative acne with acute onset. It usually affects adolescent boys who have associated musculoskeletal pain and septic fever. Osteolytic bone lesions have been reported in these patients. Severe cystic acne occurs almost equally in both sexes, but it has a less dramatic clinical course than acne fulminans and rarely causes ulcerative skin lesions and systemic symptoms. In this study we investigated the imaging features of bone lesions associated with acne fulminans and determined if patients with severe cystic acne have similar bone lesions. 18 1.2.5 Pyoderma faciale: Rosacea fulminans is a rare disease of unknown etiology which occurs mainly in postadolescent women. It is characterized by an abrupt explosive outbreak without prodromes, consisting of papules, pustules, confluent nodules with draining sinuses on the face. A dull to blue-red, cyanotic erythema of all involved facial areas is typical, often accompanied by pronounced facial edema. 19 1.4 Causes of Acne: Acne vulgaris is a mutifactorial disease affecting the pilosebaceous follicles for which Propionibacterium acnes and, less often, Propionibacterium granulosum and Propionibacterium avidum have been identified as etiological agent. 20 Acne is inflammation of the skin, due to blockage of skin's pores. Blockage occurs due to an excessive secretion from the skin's oil glands and accumulated, dead skin cells. This combination encourages the skin bacterium Propionibacterium which multiplies and causes increased skin inflammation. 14 Hyperkeratinization and formation of a plug of keratin and sebum (a microcomedo) is the earliest change. Enlargement of sebaceous glands and an increase in sebum production occur with increased androgen (DHEA-S) dehydroepiandrosterone sulfate production at adrenarche. The microcomedo may enlarge to form open comedones (blackhead) or closed comedones (milia). Comedones are the direct result of sebaceous glands becoming clogged with sebum, naturally occurring oil, and dead skin cells. In these conditions, the naturally occurring largely commensal bacterium Propionibacterium acnes can cause inflammation, leading to inflammatory lesions (papules, infected pustules, or nodules) in the dermis around the microcomedo or comedone, which results in redness and may result in scarring or hyperpigmentation. 2,21 Some causes are: 1.4.1.Genetics: Acne is a multi-factorial disease, and genetics probably contributes to the development of acne. Studies indicate that the size, number and activity of sebaceous glands are genetically determined. In addition, the concordance rate of acne in identical twins is high, confirming the role of genetics in the development of acne.

1.4.2.Diet:
A recent study concluded that dairy products contribute to the pathogenesis of acne. This is postulated to be mediated via the synthetic hormones used in cows in the milk industry. Caution must be used in interpreting such studies and the general recommendations remains for individuals to eat a well-balanced diet.

1.4.3.Hormones:
Sebaceous gland excretion may be stimulated by male sex and adrenal gland hormones. During puberty, the levels of these hormones are not elevated, but the sebaceous glands are more sensitive to them. There are certain medical conditions which can lead to inappropriately high levels of male sex hormones, thereby producing acne. 1.4.4.Drugs: Acne form eruptions can occur as an adverse drug eruption, and stopping the offending drug will often alleviate the problem. This must be done in consultation with the prescribing physician, with a detailed review of risks and benefits of stopping the offending medication undertaken. 1.4.5.Hair grooming agents-Pomade acne: Excessive use of hair pomades (also known as hair moisturizers, hair styling products and hair grease), which are often part of the hair care regime of blacks, can lead to the development of acne. This occurs especially around the hairline and forehead. Counseling and review of the hair care regime can alleviate pomade acne. 1.4.6.Cosmetics: Acne can result from heavy cosmetic use and the associated pigmentation changes may be exacerbated by harsh agents applied to the skin as part of an individual's grooming practice and vigorous washing of the skin with rubbing and scrubbing, or using puffs or abrasive sponges can also cause or worsen acne.

PLANTS USED FOR THE PROPIONIBACTERIUM ACNES
The aim of this study was to compile the antimicrobial medicinal plant used in Ayurveda and traditional medicinal system for treatment of manifestations caused by Propionibacterium acnes.
Therefore, extracts of the following plants from different families which contain different phytoconstituents like essential oils, 11 flavonoids, tannins, 24 alkaloids, 30 terpenoids, 32 volatile oil 35 and phenolic compounds 44 having potential activity against Propionibacterium acnes. Propionibacterium acnes have been most recognized as a key factor for the development of acne and the plants which are use as antiacne or to prevent acnes are enlisted in table no. 1.

CONCLUSION
Propionibacterium acnes have been recognized as pus-forming bacteria triggering an inflammation in acne. Propionibacterium acnes is a Grampositive, anaerobic microorganism, which has been most recognized as a key factor for the development of acne. 11 Acne vulgaris is a chronic inflammatory disease of the pilosebaceous follicle, characterized by comedones, papules, pustules, cysts, nodules and often scars in certain sites of predilection, namely, the face, neck, upper trunk and arms. Factors which contribute to the development of acne include hormonal imbalance, bacterial infection, stress, food, or cosmetic application. 11 The use of oral antibiotics for the treatment of acne may be associated with adverse effects. 22 The plants having phytoconstituents like alkaloids, phenolic compounds, volatile oil, essential oil, might be used for the preparation of topical herbal formulations. Currently the problem associated with the therapy for acne is that the topical products available are either cream based (mostly oily) or associated with adverse effects contributed to their chemical nature and natural remedies are more acceptable in the belief that they are safer with fewer side effects than the synthetic ones so, herbal anti-acne solution which is approximately non-toxic, safe, effective and improves patient compliance by the utilization of herbal extracts would be highly acceptable. [23][24] The importance of the acne treatment in the adult should be enhanced as it can also lead to symptoms of serious depression and anxiety. 5 The topical and oral ayurvedic compounds contain herbal agents have been reported to have value in the treatment of acne. 25 Dermatol., 1998, 134, pp.454-8. 58. Krautheim, A.;Gollnick, H. Acne: topical treatment. Clin. Dermatol, 2004, 22, pp.398-407. 59. Leyden, J. and A. Kligman. 1976 Tsai T et al. (2010)