Phytotherapy: Skin conditions

Phytotherapy (Herbs)

Phytotherapy for Skin (Dry/Itchy/Eczema)

• These skin disorders are common and need examination by a medical professional for infection/ serious underlying cause
• Emollients like arachis oil or oat extracts are typically the early treatment option
• Plant extracts are useful in such preparations

Arachis Oil

• From Arachis hypogaea (aka ground nut/peanut)
• Fixed oil including:
• Oleic glycerides (C18H14O2, monounsaturated omega-9 fatty acid)
• Linoleic acids (C18H32O2, polyunsaturated omega-6 fatty acid)
• Used in emollient creams and bath oils

Oats (Avena sativa)

• It is a widely distributed crop
• Seeds without husks are crushed into creamy white powder
• Constituents are
• Proteins (avenin, avenalin, and gliadin)
• Polyphenols (avenanthramides)
• Starch
• Soluble Polysaccharides
• Saponins (avenacosides A, B, and soyasaponin)
• Fatty acids of phytosterols including cholesterol, β-sitosterol, Δ5-avenasterol, avenoleic acid, linoleic acid, and vitamin E

Oats Therapeutic Uses

• Its colloidal fraction works well as an emollient in bath for eczema/itchy/dry skin, especially with regular use
• Avenanthramides are anti-inflammatory and anti-irritant. Cells treated with it showed TNF-alpha inhibition with subsequent interleukin-8 reduction
• Inflammation is mitigated by topical application of avenanthramides in murine models of hypersensitivity/neurogenic inflammation
• The anti-irritant activity is mediated by avenanthramides.
• Starch and beta-glucans provide protective and water-holding/moisturizing properties
• Polyphenolic compounds give antioxidant and anti-inflammatory effects
• Phenols make it a strong ultraviolet absorber

Aloe Vera (barbadensis)

• Contains polysaccharides, glycoproteins, enzymes such as carboxypeptidases and anthraquinone glycosides.
• It is mainly in the form of pure gel and used as lotion

Aloe Vera Therapeutic Uses

• Antibacterial, anti-inflammatory, emollient, and moisturizing for dermatological preparations
• Polysaccharides and some glycoproteins are soothing and immunostimulating
• Anthraquinone derivatives are antibacterial
• Enzymes from aloe vera are analgesic, inhibit thermal damage, and vascular permeability in mice.
• It is an antioxidant that induces carcinogen-metabolizing phase I enzymes (cytochrome P450 oxidases introduce reactive/polar groups)
• Used for stomach and mouth ulcers, as well as burns/wound healing
• Comparable to triamcinolone acetonide 0.1% in reducing psoriasis symptoms
• Proved superior to hydrocortisone 1% as anti-inflammatory in UV-induced erythema. It is useful in post-radiotherapy and after-sun treatment

Evening Primrose Oil (Oenothera biennis)

• A perennial ornamental plant that was inspired by North American Indians for uses in Western phytomedicine
• Only the seed oil is now used for atopic eczema

Evening Primrose Oil Constituents & Therapeutic Uses

• Seed oil contains 70% _cis-_linoleic acid and around 9% cis-Y-linoleic acid
• The Y-linoleic acid content of the oil has been extensively investigated for its therapeutic benefits
• Can be taken internally or applied externally for atopic dermatitis (eczema)
• Supplements topical dermatological diseases with omega-6 essential fatty acids
• Patients with atopic dermatitis have omega-6 imbalances
• Omega-6 essential fatty acids play a vital role in skin structure and physiology
• Deficiency replicates atopic dermatitis symptoms
• The effect of fatty acids on atopic dermatitis has yielded conflicting results. However, it has been shown to give a beneficial effect of alleviating symptoms in 4-8 weeks

Marigold (Calendula officinalis - Asteraceae)

• From southern Europe
• A well-known medicinal European plant with long pharmaceutical use

Marigold Constituents & Therapeutic Uses

• Flowerheads contain saponins (calendasaponins A, B, C, D)
• Also contains pentacyclic triterpene alcohols (faradiol, erythrodiol, calenduladiol)
• Contains flavonoids (rutin), sesquiterpene glycosides, and volatile oil/polysaccharides
• Used for wound healing and post-radiotherapy in inflammatory skin conditions due to marigold flowerhead content of lipophilic triterpene alcohols (esters of faradiol).
• Marigold extracts prevented glutathione depletion in mouse skin with oral introduction and increased gelatinase activity, beneficial to skin healing/procollagen synthesis
• Used both orally and topically in wound healing

Marigold Action Mechanism

• Extracts improved healing of incision wounds in rats and reduced the re-epithelization time.

1. Enhanced fibroblast proliferation and migration at low concentrations
2. Oil is antibacterial and antifungal in vitro, further benefits wound healing

• The Immunostimulant action is due to polysaccharide content

Witch Hazel (Hamamelis virginiana)

• Native to N. America and Canada
• Extracted and mainly used as an astringent in skin/eye inflammation

Witch Hazel Constituents & Therapeutic Uses

• The leaves and bark are rich in tannins (e.g., hamamelitannin)
• Used to treat hemorrhoids, bruises, skin irritations, spots, and eye redness
• Hamamelitannin inhibits TNF-mediated endothelial cell death without altering TNF-induced upregulation of endothelial adhesiveness
• Its action makes it useful as an anti-hemorrhagic

Centella Asiatica (Apiceae)

• Commonly known as Indian Pennywort or Brahmi
• It is a medicinal plant used worldwide

Centella Asiatica Growth & Constituents

• Grows in streams/low, wet areas so it is prone to sewerage exposure/contamination with bacteria/metals
• Used as a vegetable/in salads in countries like Sri Lanka
• Major constituent of the plant is pentacyclic triterpenes (asiatic acid, asiaticosides, brahmoside, brahmic acid, brahminoside, centelloside, etc.)
• Also contains flavonoids (kaempferol, quercetin, etc.) and volatile oils (α-humulene, β-caryophyllene, etc.)

Centella Asiatica Therapeutic Uses

• General tonic
• Skin conditions (wound healing, inflammation, psoriasis by inhibiting keratinocyte replication, stretches during pregnancy)
• Taken internally for mental disorders to improve memory, and for atherosclerosis/venous insufficiency
• There are few clinical trials, but pharmacological studies support its use in skin conditions

Centella Asiatica Acceleration Mechansims for Wound Healing

• Extracts tested in a rat incision wound model improved the rate of epithelization and wound contraction
• Stimulation of extracellular matrix accumulation in rat experimental models
• Asiatic acid stimulated collagen synthesis
• Increased collagen secretion