Citrus fruits (Lemon Fruit) are cultivated worldwide are commonly known for their valuable nutritional, pharmaceutical and cosmetic properties.
Rich in citric acid, ascorbic acid, minerals, flavonoids and essential oils.
SKIN DEPIGMENTATION
Lemon fruit contains Vitamin C which is a depigmenting agent. It decreases melanin synthesis due to its ability to interfere with the action of tyrosinase, the rate-limiting enzyme in melanogenesis.
Vitamin C interacts with the copper ions at tyrosinase-active sites and inhibits the action of the enzyme tyrosinase thereby decreasing melanin formation by reducing the DOPA and DOPA-quinone generated by tyrosinase.
ANTIOXIDANT
Lemon juice naturally contains Vitamin C, phenolic acid and flavonoids; antioxidants that help keep skin even-toned by reducing UV-induced skin hyperpigmentation.
It has free radical scavenging activity to protect the cellular membrane from inflammation triggered by oxidative stress. It helps to inhibit the harmful free radical-mediated reactions caused by oxidants found in the body and the environment.
ASTRINGENT
Lemon extract tends to provide a gentle astringent effect, which causes the contraction of skin cells to tighten large pores and strengthen the skin. It regulates the formation of unwanted blemishes by decreasing sebum production.
ANTIMICROBIAL
Lemon Fruit has antibacterial properties due to its acidic pH. The acidic pH can inhibit bacterial growth by decreasing the internal pH of the bacterial cells and inhibiting the bacterial cell wall.
ANTI-INFLAMMATORY
Lemon fruit has antibacterial properties and anti-inflammatory properties that can help soothe skin irritations. It can suppress UVB-induced COX-2 expression and prostaglandin production in HaCaT cells. Therefore, can promote wound healing to prevent post-inflammatory hyperpigmentation.
COLLAGEN PRODUCTION
Vitamin C present in Lemon fruit is essential for collagen biosynthesis. It has been proposed that Vitamin C influences quantitative collagen synthesis in addition to stimulating qualitative changes in the collagen molecule.
Vitamin C serves as a co-factor for the enzymes prolysyl and lysyl hydroxylase, the enzymes that are responsible for stabilizing and cross-linking the collagen molecules.
Vitamin C also directly activates the transcription of collagen synthesis and stabilizes procollagen mRNA, thereby regulating collagen synthesis.
In addition, Vitamin C increases the gene expression of collagen and synthesis of the tissue inhibitor of MMP-1, which decreases collagen degradation.
WOUND HEALING
Vitamin C has a beneficial effect on wound healing. This is directly related to its cofactor activity for the increased collagen production, anti-inflammatory and antioxidant properties.
EXFOLIATION
Lemons also contain citric acid, which helps to exfoliate dead skin cells. When applied to the skin, it stimulates the exfoliation of epidermal cells in the stratum corneum by interfering with the ionic bonding between these cells.
This results in the sloughing off dull and rough skin and promotes cellular renewal to fade mild hyperpigmentation. The new skin revealed beneath is brighter and more radiant.
Citrus fruits are safe for use in both rinse-off and leave-on cosmetic products when formulated to be non-sensitizing and non-irritating.
https://online.personalcarecouncil.org/ctfa-static/online/lists/cir-pdfs/FR691.pdf
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4690266/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3673383/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5605218/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7027822/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5579659/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3941867/