Known by many names across the region—กระแจะ, พญายา, ขะแจะ, ตุมตัง, and others—Hesperethusa crenulata is a tree whose bark, stem, and wood have long been treasured in traditional Southeast Asian medicine. In Thailand, the engraved word “กระแจะ” conjures centuries of healing practices, folk wisdom, and even romance, as this herbal ingredient not only soothes physical ailments but is often mentioned in the poetry and cultural traditions of the central plains, the north, and northeast. Today, กระแจะ’s ancient legacy is finding new life as research teams shine the spotlight on its potent phytochemicals and their promising applications for beauty, health, and disease prevention.
For generations, Thai healers have reached for the pale, aromatic wood of the กระแจะ tree to make remedies that address everything from skin woes to fevers. According to respected Thai herbal compendiums—including the National Herbal Database and contemporary summaries by regional experts—the inner wood and heartwood of กระแจะ are often combined with other canonical Thai herbs in both traditional mixtures and single-ingredient preparations (NBT Herb Database; Ubon Ratchathani University Pharmacy Herbarium; Medthai.com). These remedies have been used for topical and oral administration in attempts to clear skin conditions, reduce inflammation, act as a fragrant deodorizer, and even as aphrodisiacs in ancient courtly recipes.
The Thai connection to กระแจะ runs deep. For example, literary records from Siam’s early modern period mention a scented ball made with ground กระแจะ as part of the toilette of palace women and men. This “perfumed heartwood,” often an ingredient in love potions and court beauty elixirs, reflected both the sensual and the medicinal aspects of the herb. Community healers in different regions have known it by local names: พญายา in Ratchaburi, ขะแจะ in the North, and ตุมตัง in the Northeast, each with its own unique cultural context (Medthai.com). In ancient recipes, the wood was prized for its pleasant fragrance, leading to its use in deodorants, in incense for religious ceremonies, and even to freshen stored clothes.
Modern researchers, intrigued by its widespread popularity, have examined the chemical constituents that might account for these effects. A comprehensive systematic review conducted in 2021 and published in the journal Cosmetics (MDPI, 2021) summarizes the state of contemporary scientific understanding. Scientists have isolated an impressive range of bioactive compounds in the stem, bark, leaves, and fruit of Hesperethusa crenulata, including potent polyphenols, flavonoids, coumarins (notably marmesin and suberosin), alkaloids, terpenes, and steroids.
What do all these complicated names mean for the everyday Thai seeking safe, effective herbal solutions? In plain language: many of these substances are powerful antioxidants, which can scavenge damaging free radicals, support anti-ageing processes, and perhaps even help to prevent some chronic diseases. Coumarins, for example, are not only recognized for their sweet scent but also their anti-inflammatory, anti-microbial, and photoprotective properties. Marmesin, another coumarin in the bark, has been shown to absorb a wide range of UV-A radiation, which underpins its application as a natural sunscreen ingredient (MDPI, 2021).
A significant body of laboratory studies, especially those using extracts from the tree’s bark, has explored the health-protecting virtues of กระแจะ. Tested for antioxidant capacity using standard assays such as DPPH and total phenolic content, extracts—particularly those prepared with ethanol and methanol—show robust radical scavenging activity. Scientists at Thai universities and their international collaborators report that the antioxidant effects are often on par with or even exceed those of well-known substances like vitamins C and E (Wangthong et al., 2010; MDPI, 2021).
But antioxidants are only the beginning. Researchers have also demonstrated significant anti-inflammatory effects, particularly with extracts from the bark. When tested on immune cell cultures, various solvents’ extracts of กระแจะ were able to dampen inflammatory signals—with some performing on par with, or better than, standard pharmaceutical anti-inflammatories at non-toxic dosages (MDPI, 2021). Anti-inflammatory remedies are traditionally valued in Thai folk medicine for treating injuries, skin irritation, and arthritic pain—lending modern credibility to age-old uses.
Safety, of course, is at the forefront of modern herbal research. While some cytotoxicity was observed at high concentrations with certain organic-solvent-derived extracts, the original bark powder and water-based preparations—similar to traditional usage—showed only minimal toxicity in cell culture studies. Importantly, no genotoxicity (the potential to damage genetic material) was detected in the standard laboratory tests (Wangthong et al., 2010). This preliminary safety evidence aligns with the long history of safe use in both folk and courtly contexts, though it must be stressed that excessive or undiluted applications may still carry risks.
Another area where กระแจะ shines—as both traditional wisdom and laboratory results concur—is skin health. In Myanmar, where the tree is known as Thanaka, the powdered bark is iconic for its cosmetic use, protecting against the sun and beautifying the skin for over 2,000 years. Scientific studies have expanded on this reputation: besides confirmed UV-absorbing qualities, extracts have shown mild antibacterial activity against problematic skin bacteria such as Propionibacterium acnes and Staphylococcus aureus, supporting its folk use for acne and skin infections (MDPI, 2021). Cosmetic manufacturers in Thailand, Myanmar, and Malaysia now incorporate standardized extracts in facial powders, scrubs, cleansers, and soaps, touting benefits from anti-ageing and skin-brightening to regulating oil and soothing rashes.
Thai folk medicine traditionally goes beyond cosmetic or simple topical uses. Some classical formulations include oral administration—for instance, as part of a mixture for reducing fever, regulating digestion, or serving as a general tonic (NBT Herb Database; Medthai.com). However, scientific evidence for the efficacy and safety of these internal applications remains limited compared to the robust body of data supporting topical uses.
Culture, legend, and ritual have also shaped attitudes toward this remarkable plant. Across central Thailand, กระแจะ was long associated with love and allure, often included in royal perfumes, wedding rituals, and religious ceremonies to invite favorable spirits or ensure marital bliss. In the broader context of Southeast Asia, its cousin “Thanaka” serves as both a visible symbol of cultural identity and a practical remedy, with even ancient poems and murals capturing its esteemed role in daily life (MDPI, 2021).
What does the future hold for กระแจะ in Thai wellness? Modern developments suggest continued growth, especially in cosmeceutical and sustainable pharmacy fields. The push toward “green” extraction methods, using environmentally gentle solvents such as glycerol instead of harsh chemicals, is making plant extracts safer and more acceptable for sensitive skin and environmentally conscious consumers. Researchers encourage more careful, collaborative work to further isolate the specific molecules responsible for observed benefits and clarify mechanisms—key steps in developing standardized, effective natural therapies (MDPI, 2021).
For the Thai public and wellness enthusiasts, the practical takeaway is twofold. First, recognize that กระแจะ’s traditional uses for skin soothing, sun protection, and topical health enjoy significant scientific validation—so incorporating standardized, quality-controlled extracts or reputable topical products may offer real benefits. Second, exercise caution and always consult with qualified healthcare providers before ingesting or using traditional herbal remedies, especially in concentrated forms or as part of complex mixtures. While research affirms the low toxicity of most topical applications, individual sensitivities, allergies, or interactions cannot be ruled out.
In summary, กระแจะ (Hesperethusa crenulata) is more than a relic of folk medicine—it is a living symbol of how Thai healing wisdom can intersect fruitfully with modern science. From royal courts to community healers and now to laboratory benches and beauty counters, this remarkable tree continues to inspire hope—as remedy, ritual, and reservoir of new knowledge waiting to be unlocked.
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