Botanicals for Solar Photoprotection

UV radiation accelerates skin aging, but emerging research highlights the protective potential of certain botanicals.

Jul 08, 2025

Last week, I wrote about how chemical and mineral ingredients in sunscreen work by absorbing, reflecting, or scattering ultraviolet radiation (UVR) as it hits the skin—read that post first in case you missed it. This week, I’m focusing on how botanical ingredients help to protect the skin against UVR damage.

SPECIAL NOTE: Join me this Thursday, July 10th at 6:00 PM Italian time/ 12:00 pm EST / 9:00 AM PT via livestream on Substack! I’ll be streaming from a natural skincare workshop hosted by the Community of Ginestra, located in Basilicata province, southern Italy. The workshop will be in Italian with live translation to English.

The Skin Aging Process

What is Photoaging?

Photoaging refers to the premature aging of the skin caused by prolonged and repeated exposure to UVR from the sun. Unlike chronological aging, which is driven by internal biological processes, photoaging is an external, environmentally triggered process. UVR, especially UVA and UVB penetrates the skin and generates reactive oxygen species (ROS), which damage components of cells, degrade collagen in the skin, and disrupt normal pigment production. Photoaged skin is characterized by fine lines, wrinkles, lentigines (sunspots), uneven pigmentation, and a rough, leathery texture. When combined with other environmental oxidative stressors (e.g., heavy alcohol consumption, smoking, exposure to pollutants), these aged skin characteristics are even more prominent.

What about collagen breakdown?

LEFT: In youthful skin, collagen fibers form a strong and supportive network that gives skin its firmness. This network also provides a healthy environment for collagen producing fibroblasts to stay active. These cells thrive when they can stretch and feel tension from their surroundings, which helps keep collagen levels steady and healthy. MIDDLE: With repeated sun exposure, harmful ROS build up. These trigger a chain reaction that reduces new collagen production and activates enzymes (matrix metalloproteinases, MMPs) that break down existing collagen. RIGHT: Over time, broken collagen fragments pile up and weaken the skin’s structure. Fibroblasts sense this damage and shift into a less active state, making even less collagen and more of the MMPs that break it down. This creates a cycle of ongoing collagen loss, which leads to thinner, more fragile skin and visible signs of aging. Figure source: Rittié L, Fisher GJ. Natural and sun-induced aging of human skin. Cold Spring Harb Perspect Med. 2015 Jan 5;5(1):a015370. doi: 10.1101/cshperspect.a015370. PMID: 25561721; PMCID: PMC4292080.

Collagen is a key protein that gives skin its strength and firmness. When skin is exposed to UVR, it produces harmful ROS (described above). These ROS trigger enzymes (MMPs) that break down collagen in the deeper layers of the skin. Over time, the broken collagen fragments build up and change the skin’s structure. Skin cells called fibroblasts, which normally make new collagen, become less active in this damaged environment. They stop making as much collagen and instead produce more of the enzymes that break it down. This creates a self-sustaining cycle where collagen keeps getting broken down faster than it can be replaced. Even though the fibroblasts themselves are still capable of making collagen, they stop doing so because of the damaged environment around them. This ongoing breakdown of collagen leads to the visible signs of photoaging, like wrinkles, sagging, and loss of elasticity.

How Does the Skincare Market Address Photoaging?

The skincare market is brimming with topical formulations marketed for anti-aging, many of which contain vitamins, minerals, and botanical extracts. These ingredients are proposed to work through mechanisms such as neutralizing free radicals, stimulating collagen synthesis, or inhibiting collagen breakdown, ultimately aiming to slow or reverse the visible signs of photoaging. A lot of these formulas, rich in polyphenolic compounds, tout antioxidant properties.

Photoprotective Botanicals

There are many different medicinal plants and fungi used in skincare products for their skin protective effects. A 2015 expert opinion review article examined the patent literature on this topic, revealing some interesting details on how some of these ingredients are purported to work. Here, I’ve broken things down by mechanism of action and list examples of species that fit under these mechanistic categories:

Antioxidant Defense Against Free Radicals

One of the main ways botanicals protect the skin from photoaging is through their antioxidant activity. UVR generates ROS, which damage cellular lipids, proteins, and DNA, accelerating the aging process. Botanical antioxidants (such as polyphenols) neutralize these ROS, reducing oxidative stress and preventing or repairing skin damage. For example, Adansonia digitata (baobab) extracts have demonstrated the ability to scavenge free radical ROS like hydroxyl and superoxide ions, while also reducing UVA-induced lipid peroxidation in fibroblasts and mitigating UVB-induced damage in keratinocytes. A patented blend (5:3 ratio, patented by Nutragenesis LLC) of Withania somnifera (ashwagandha) and Phyllanthus emblica (Indian gooseberry) showed high oxygen radical absorbance capacity (ORAC) and effectively inhibited hyaluronidase, an enzyme involved in skin degradation. Similarly, an extract from the Antarctic grass Deschampsia antarctica, patented by Vitrogen, displayed antioxidant properties that dissipate excess UV radiation and support skin photoprotection.

Preserving and Stimulating Collagen

UVR exposure accelerates the breakdown of collagen by upregulating enzymes such as matrix metalloproteinases (MMPs), especially MMP-1, which degrade the structural integrity of the dermis. Botanicals that either inhibit this breakdown or enhance collagen synthesis can improve skin firmness and reduce the appearance of wrinkles. Gum mastic (Pistacia lentiscus) (see this earlier post I wrote on this plant in Greece!), when applied topically, was shown to stimulate both collagen and glycosaminoglycan production, enhancing skin elasticity. Additionally, the essential oil of Laserpitium siler (laserwort) reduced MMP-1 levels and promoted collagen expression in keratinocytes, protecting the dermal matrix from UV-induced degradation.

Reducing Inflammation from UV Damage

Inflammation is a key contributor to photoaging, driven by UVR-induced activation of inflammatory pathways such as NF-κB, COX-2, and iNOS. Certain botanicals possess anti-inflammatory properties that counteract these effects. A water-soluble extract from Solanum incanum (a nightshade found in Africa and the Middle East) significantly reduced levels of inflammatory markers and improved skin barrier function by decreasing transepidermal water loss (TEWL) in UVB-exposed skin. Extracts from Grifola frondosa (maitake mushroom) were found to inhibit collagenase and tyrosinase, suggesting roles in both anti-inflammatory and anti-pigmentation effects. Likewise, Magnolia sieboldii extracts prevented UV-induced keratinocyte and fibroblast death and reduced collagenase production, demonstrating both protective and reparative actions against photoaging.

Enzyme Inhibition for Skin Structure and Pigment Protection

Botanical extracts can also protect the skin by inhibiting enzymes that degrade structural proteins or promote pigmentation changes. This includes collagenase, which breaks down collagen; tyrosinase, which regulates melanin synthesis; and hyaluronidase, which contributes to the breakdown of hyaluronic acid. The combination of ashwagandha and Indian gooseberry inhibited hyaluronidase activity, preserving moisture and skin structure. Grifola frondosa (hen-of-the-woods mushroom) demonstrated dual inhibition of collagenase and tyrosinase, suggesting benefits for both wrinkle reduction and prevention of hyperpigmentation.

The Takeaway

While these botanical ingredients (plus many others not included here due to space limitations) show promise in solar photoprotection for the skin, it is important to note that these are not replacements for the use of protective physical barriers (hat and protective clothing), sunscreen, or behaviors to reduce overexposure to UVR. To receive the most benefit in the reduction of skin photoaging, it is important to take a holistic approach to skin care.

Yours in health, Dr. Quave