Experimental Design Route Administered Mechanism of Action Findings
Synthesized compounds
Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine (BEMT) In vitro skin permeation test Topical Absorbs UVA and UVB rays ranging from 280-400 nm Maximal topical applications of 6% BEMT in sunscreen formulation did not contribute to systemic exposure or estrogenic effects[@277141; @277144]
Bis (diethylamino hydroxybenzoyl benzoyl) piperazine (BDBP) In vivo Topical Absorbs wavelengths in the UV/visible border region (385-405 nm) The addition of BDBP affords more protection against pigmentation than a conventional formulation with the 385 nm source[@277145]
Natural compounds
Cyanobacterium, syctonemin In vivo (mice model) and in vitro Topical Secrete mycosporine-like amino acids in response to UV-AB light, which have UV absorption properties Inhibits skin inflammation by down-regulating NF-kB activity and decreasing expression of TNF-a. Performs as a multi-function ingredient for skin care[@277146; @277166]
Usnic acid In vivo and in vitro Topical Contains UV absorbing properties Demonstrated UV protection factors superior to a commercial sunscreen spray with an SPF of 5, octyl methoxycinnamate (OMC), and butyl meth-oxydibenzoylmethane (BM-DBM)[@277148; @277149; @277167]
Green coffee oil In vivo and in vitro Topical Rich source of antioxidants and polyphenols. High chlorogenic acid activity to facilitate wound healing GCO showed a synergistic effect in SPF value when it was associated with the synthetic sunscreen ethylhexyl methoxycinnamate, leading to an increase of 20% in SPF35,53–55
Sesame oil In vitro Topical Contains vitamin E and phenolic compounds to absorb UV rays and act as antioxidant and anti-inflammatory agents Sesame oil resists 30% of UV rays, whereas coconut, peanut, olive, and cottonseed oils block out about 20%[@277151; @277171; @277172]
Green tea In vivo (mice model) and in vitro Topical or oral The main active ingredient, epigallocatechin-3-gallate (EGCG), works as an anti-inflammatory agent, antioxidant, and sunscreen Topical green tea applied to human skin yields a photoprotective effect, reducing the number of sunburns cells, protecting epidermal Langerhans cells from UV damage, and reducing the DNA damage that forms after UV radiation. Green tea further decreases melanoma cell formation after topical and oral administration in mice[@277151; @277173]
Krameria triandra root extract In vitro Topical Rich in tannins to provide UV protection and reduce inflammation Significantly and dose-dependently decreased the loss of cell viability and intracellular oxidative damage, absorbed 25% to 30% of the amount of UV radiation typically absorbed by octyl methoxycinnamate[@277151; @277152]
Propolis In vivo (mice model) and in vitro Topical Antioxidant, contains broad spectrum UVB and UVA photoprotection Formulations containing 40% of the hydroalcoholic propolis extract possess an SPF value of 10.[@277153] When propolis is added to titanium dioxide, the SPF value increased from 20 to 50–60 showing a high synergic effect[@277154]
Silymarin In vivo (mouse model) Topical Antioxidant, activates p53, prevents UVB-induced immune suppression Mice treated with silymarin either before or after UV exposure illustrated diminished infiltration of leukocytes especially, CD11b+ and also decreased number of cells producing H2O2 and nitric oxide suggesting silymarin to be an anticarcinogenic and anti-inflammatory agent[@277151; @277161; @277162; @277174]
Polypodium leucotomos extract In vivo (mouse and human models) Oral Antioxidant, inhibits release of cytokines Demonstrated a favorable safety profile while protecting UVR-induced sunburn reaction and UVA-induced phototoxicity47–50