Ultraviolet A protective potential of plant extracts and phytochemicals

Abstract

Chronic exposure to solar radiation is related to an increased incidence of various skin disorders, including premature skin aging and melanoma and non-melanoma skin cancers. Ultraviolet (UV) photons in particular are responsible for skin damage. Solar UV photons mainly belong to UVA wavebands, however UVA radiation has been mostly ignored for a long time. At the cellular level, UVA photons mainly provoke indirect oxidative damage to biomolecules via the massive generation of unstable and highly reactive compounds. Human skin has several effective mechanisms that forestall, repair and eliminate damage caused by solar radiation. Regardless, some damage persists and can accumulate with chronic exposure. Therefore, conscious protection against solar radiation (UVB+UVA) is necessary. Besides traditional types of photoprotection such as sunscreen use, new strategies are being searched for and developed. One very popular protective strategy is the application of phytochemicals as active ingredients of photoprotection preparations instead of synthetic chemicals. Phytochemicals usually possess additional biological activities besides absorbing the energy of photons, and those properties (e.g. antioxidant, anti-inflammatory) magnify the protective potential of phytochemicals and extracts. Therefore, compounds of natural origin are in the interest of researchers as well as developers. In this review, only studies on UVA protection with well-documented experimental conditions are summarized. This article includes 17 well standardized plant extracts (Camellia sinensis (L.) Kuntze, Silybum marianum L. Gaertn., Punica granatum L., Polypodium aureum L., Vaccinium myrtillus L., Lonicera caerulea L., Thymus vulgaris L., Opuntia ficus-indica (L.) Mill., Morinda citrifolia L., Aloe vera (L.) Burm.f., Oenothera paradoxa Hudziok, Galinsoga parviflora Cav., Galinsoga quadriradiata Ruiz et Pavón, Hippophae rhamnoides L., Cola acuminata Schott & Endl., Theobroma cacao L. and Amaranthus cruentus L.) and 26 phytochemicals.

The Effects of Morinda citrifolia (Noni) on the Cellular Viability and Osteogenesis of Stem Cell Spheroids

“…Noni is a tropical tree with an ovoid yellow fruit, and is distributed widely in areas of Southeast Asia, Australia, Hawaii, Tahiti and Micronesia [ 23 ]. The Noni fruit is consumed as food and has been approved as a commercial food [ 24 ].…”

Botanicals for photoprotection

“…Nowadays, it is chiefly marketed as an oral hepatic supplement and has been used to treat hepatitis, alcoholic liver diseases, cirrhosis, and toxin-induced hepatotoxicity. The polyphenols present in silymarin, which is more appropriately termed flavonolignans, are silybin, silychristin, silydianin, isosilybin, and 2,3-dehydrosilybin [32][33][34] .…”

Theoretical Study of Radical Inactivation, LOX Inhibition, and Iron Chelation: The Role of Ferulic Acid in Skin Protection against UVA Induced Oxidative Stress

“…Prolonged exposure may result in oxidative stress caused by radiation induced generation of reactive oxygen species (ROS, e.g., 1 O 2 , • OH, O 2 •− , O 3 , and H 2 O 2 ). The main adverse health effects of UV radiation are premature skin aging, immune suppression, increased risks of skin cancer, and eye disorders and diseases [ 1 , 2 ].…”

“…Antioxidants may prevent ROS induced skin damage only when they are present in relevant concentration in situ (at the skin’s surface but also inside the skin) before Sun exposure [ 16 , 17 ]. Ferulic acid (FA) is well absorbed by the skin and is widely used in skin formulations [ 2 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. FA is a widespread dietary phytochemical that can be found in cereal bran, citrus juice, coffee, and numerous vegetables and fruits [ 18 , 27 , 28 ].…”