Natural Extracts and Cosmetics Containing Natural Extracts
1 Functions of Natural Extracts
1.1 Improving Skin Appearance
1.1.1 Skin Whitening and Spot Reduction
Whitening agents have long been a major focus in cosmetic research. Early whitening ingredients such as mercury compounds, corticosteroids, and hydroquinone offer rapid results but are associated with significant toxicity, bioaccumulation, and irritation. Later-used agents such as kojic acid and vitamin C derivatives improved safety but still faced challenges, including instability and slow onset of action.
Natural whitening ingredients-characterized by high safety, mild action, and multi-target efficacy-have become an important trend. They exert brightening effects through mechanisms such as inhibiting tyrosinase, reducing melanin synthesis, providing antioxidant protection, regulating melanocyte activity, and enhancing microcirculation.
1.1.2 Sun Protection
Conventional UV filters include physical blockers (e.g., titanium dioxide, zinc oxide) and chemical absorbers (e.g., cinnamates, benzotriazoles). Physical filters can leave a heavy white cast, while chemical filters may oxidize, exhibit poor photostability, cause irritation in sensitive skin, or pose environmental risks.
Natural UV-protective ingredients are milder and offer broad-spectrum absorption and antioxidant benefits. Plants such as aloe vera, sophora flower, clove, and kuding tea contain flavonoids, terpenoids, and phenylpropanoids that absorb UV radiation, suppress free radical formation, protect keratinocytes and skin immune function, and help prevent photoaging.
1.2 Regulating Skin Condition
1.2.1 Anti-aging
Natural extracts show multi-target anti-aging effects through:
Antioxidation-reducing free-radical–induced skin damage;
Maintaining dermal structure-inhibiting MMPs or promoting TIMPs;
Photoprotection-minimizing UV-induced photoaging.
Compared with synthetic anti-aging compounds, natural extracts offer higher safety, lower irritation, and more sustained and gentle effects, making them increasingly popular in anti-aging skincare formulations.
1.2.2 Moisturizing
Natural moisturizing ingredients meet the demand for low-irritation and effective hydration. Their mechanisms include:
Polyphenolic hydroxyl groups form hydrogen bonds with water to lock in moisture.
Ceramides repair the skin barrier and restore the lipid structure of the stratum corneum.
Upregulation of AQP3 aquaporin channels to enhance transmembrane water transport;
Inhibition of hyaluronidase to reduce hyaluronic acid degradation.
Common moisturizing botanical extracts include perilla, apricot seed, and loosestrife.
1.3 Hair-Care Applications
Hair-care formulations often include herbal extracts with nourishing, strengthening, or astringent properties to reduce hair loss and promote growth. Frequently used ingredients include Polygonum multiflorum (He Shou Wu), Schisandra, black sesame, biota leaves, ginseng, and Eclipta prostrata. These botanicals may work through blood circulation enhancement, replenishing effects, or astringency to support healthy hair growth.
1.4 Other Functions
1.4.1 Emulsifying Properties
Some natural extracts contain saponins, gums, proteins, cholesterol, or lecithin, which function as natural emulsifiers or stabilizers, improving the sensory profile and stability of emulsions.
1.4.2 Transdermal Penetration Enhancers
Chemical penetration enhancers such as azone and laurocapram are effective but may irritate the skin with long-term use. Natural enhancers-including peppermint oil, eucalyptus oil, clove oil, cnidium oil, angelica oil, and ligusticum chuanxiong oil-are safer alternatives with strong permeation effects and mild irritation.
1.4.3 Fragrance Ingredients
Natural fragrances are derived from flowers, fruits, leaves, roots, stems, and bark of plants, or from natural animal sources such as musk and ambergris. They impart a pleasant scent and may exhibit mild antimicrobial properties.
1.4.4 Antimicrobial and Preservative Effects
Common synthetic preservatives (parabens, imidazolidinyl urea, isothiazolinones) raise safety concerns. Natural antimicrobial compounds, including alkaloids, paeoniflorin, ginsenosides, baicalin, and various flavonoids, provide antibacterial, anti-inflammatory, and anti-spoilage effects, making them attractive alternatives.
1.5 Examples of Cosmetics Containing Natural Extracts
Most skincare products incorporate two or more natural extracts such as seaweed, aloe vera, soybean extract, or traditional herbal extracts. These ingredients contribute moisturizing, anti-inflammatory, and brightening effects. Formulation considerations include dosage, incorporation temperature, and compatibility among multiple natural actives.
2 Plant Extracts
Plant extracts are derived from botanical materials using physical and chemical extraction methods that retain the structural integrity of active constituents. Based on composition, they may include glycosides, organic acids, polyphenols, polysaccharides, terpenoids, flavonoids, and alkaloids. Based on form, they can appear as oils, oleoresins, powders, or crystalline substances.
China's plant extract industry has developed rapidly with advances in enzyme-assisted extraction, ultrasound, supercritical CO₂ extraction, and membrane separation technologies. Commonly used botanicals include aloe vera, ginseng, angelica, and licorice.
Representative formulation examples:
Skincare cream for improving hormone-dependent dermatitis, containing aloe vera and Centella asiatica extracts
Natural anti-allergy toner containing Centella, Scutellaria, Polygonum cuspidatum, tea leaf, chamomile, and rosemary extracts
3 Animal Extracts
Although used less frequently than plant extracts, animal-derived ingredients serve important roles in cosmetics. Common examples include placental extracts, honey, propolis, royal jelly, mink oil, horse oil, and pearl powder. These ingredients are valued for their moisturizing, antioxidant, and skin-repairing effects.
Representative formulations:
Night cream containing sheep placental peptide S12
Moisturizing lip balm formulated with beeswax, honey, tea polyphenols, and yeast extract
4 Other Natural Extracts
Beyond plant and animal sources, fungi (e.g., Ganoderma, Poria), marine-derived substances (marine collagen, chitin, chitosan), microbial enzymes, deep-sea water, sea salt, and marine mud are widely applied, particularly in cleansing and moisturizing products.
Representative applications:
Enzymatic facial cleanser containing herbal complex enzyme and Sapindus extract
Herbal enzyme complex including phellodendron, mugwort, saffron, honeysuckle, ginseng, and other traditional herbal materials
Stretch-mark removal body lotion formulated with chitin, borage oil, poria, Centella asiatica, alfalfa, angelica extract, and various natural actives.
