Acne vulgaris is a pervasive dermatological pathology characterized by the inflammation of sebaceous units within hair follicles. Onset of acne coincides with pubertal development and increased sebum production. Therefore, the prevalence is highest in adolescents. The pathogenesis of acne vulgaris is complex and multifactorial, and involves increased production of cutaneous sebum, hyperplasia of sebaceous glands under androgenic influence, ductal obstruction due to increased desquamation of keratinocytes, and infiltration of inflammatory cells.

Psoriasis is an immune-mediated inflammatory disease with a genetic predisposition. It is a chronic autoimmune inflammatory disorder associated with a breakdown of the skin barrier and immune system dysregulation. The disease affects approximately 125 million individuals worldwide, with prevalence rates varying from 0.1% to 8%. The onset of psoriasis has 2 peaks: at age 15 to 20 years (more common in females), and over the age of 40 (equal sex distribution). Initial management of mild to moderate psoriasis involves the use of topical treatments, such as emollients or corticosteroids.

Atopic dermatitis is a chronic inflammatory disorder associated with a breakdown of the skin barrier and immune system dysregulation. The disease predominantly manifests in childhood, affecting 15-25% of children globally, with 7-10% of cases persisting into adulthood. 

Topical therapeutics for atopic dermatitis management can be grouped into four categories based on their mechanisms of action: alleviating itchiness, suppressing immunity, attenuating inflammation, and inducing cell death.

Rosacea is a chronic inflammatory facial skin condition defined by persistent redness, visible blood vessels, and inflammatory lesions. Affecting 2% to 10% of the global adult population, it is most frequently diagnosed in fair-skinned individuals.  Its complex cause involves a combination of immune system overactivity, neurovascular dysfunction that results at least in part from the abnormal processing of cathelicidin LL-37, an antimicrobial peptide. 

Dandruff and Seborrheic Dermatitis exist on a continuous clinical spectrum. While dandruff is considered the mild, non-inflammatory version localized to the scalp, Seborrheic Dermatitis is a chronic inflammatory condition that can affect the face, chest, and body.
The development of Seborrheic Dermatitis/Dandruff is driven by a complex interaction between the host's skin, oils, and microorganisms.

Background of anti-C. acnes lipase activity

Background of in vitro-biofilm

Background of Minimum bactericidal concentration (MBC)

The Minimum Bactericidal Concentration (MBC) is the lowest concentration of an antimicrobial agent needed to kill at least 99.9% of a specific bacterial population after a defined period of incubation.
While the Minimum Inhibitory Concentration (MIC) is the minimum concentration that prevents visible growth, the MBC is the minimum concentration needed to achieve a lethal effect.

Background of Minimum inhibitory concentration (MIC)

The minimum inhibitory concentration (MIC) is the lowest concentration of an antimicrobial that prevents visible growth of a microorganism. 

Determining the MIC for any new antimicrobial is a fundamental step in its development:

Background of Model of in vitro human scalp microbiota

• Based on 454 sequencing of the scalp microbiome, the two most abundant bacterial genera found on the scalp surface are Staphylococcus and Cutibacterium, while Malassezia is the main fungal inhabitant (Grimshaw et al., 2019).
• The human scalp hosts an unusually low diversity microbiota dominated by three species: S. epidermidis, C. acnes and M.