Engineered Sesame Oil Variants Show Skin-Lightening and Wound-Healing Potential

Sesame oil has been a staple of kitchens and traditional medicine cabinets for thousands of years, but a new study suggests it may be on the verge of a second career in high-end skincare. Researchers report in the Journal of Agriculture and Food Research that a controlled catalytic trick can transform ordinary cold-pressed sesame oil into two chemically distinct functional oils, one enriched in the antioxidant sesamol and the other in the lignan asarinin. In laboratory and zebrafish experiments, these engineered oils displayed markedly different dermatological talents: the sesamol-rich oil proved to be a strikingly effective inhibitor of melanin production, while the asarinin-rich oil excelled at promoting tissue regeneration and calming inflammation after injury.

The team, led by Yuan-Qing Luo of Henan University of Technology and colleagues, started from a well-known chemical paradox. Cold-pressed sesame oil retains abundant lignans, principally sesamin and sesamolin, which lend the oil oxidative stability on the shelf but carry no free phenolic hydroxyl groups and therefore little intrinsic antioxidant or anti-tyrosinase power. Roasting generates the potent antioxidant sesamol by degrading sesamolin, but it also produces an intense aroma that is unwelcome in cosmetic formulations, and industrial refining strips out sesamol and tocopherols altogether. The researchers’ solution was a solid acid-catalyzed in situ conversion, using an oxalic acid-modified mesoporous molecular sieve catalyst added directly to cold-pressed oil at 80 degrees Celsius, selectively converting the endogenous lignans into more active derivatives without creating off-flavors.

By tuning the reaction time, the team produced two bespoke oils. A short 20-minute catalytic treatment yielded a sesamol-rich oil containing 132.25 milligrams of sesamol per 100 grams, while a longer 180-minute treatment produced an asarinin-rich oil with 356.77 milligrams of asarinin per 100 grams. Untreated cold-pressed oil contained neither compound, only its native sesamin and sesamolin. Crucially, gas chromatographic analysis showed that the fatty acid backbone of the oil was essentially untouched: oleic acid and linoleic acid remained at roughly 40 and 44 percent of total fatty acids in all three samples, preserving the emollient and barrier-repair properties that make the oil matrix valuable in cosmetics. Some loss of gamma-tocopherol and phytosterols occurred, apparently through non-selective adsorption onto the mesoporous catalyst, but this was similar in both treated oils.

The first functional test targeted tyrosinase, the copper-containing enzyme that catalyzes the rate-limiting steps of melanin synthesis and stands as the principal drug target for skin-lightening agents. At 1000 micrograms per milliliter, the sesamol-rich oil inhibited tyrosinase by 91.0 percent, statistically indistinguishable from the pharmaceutical benchmark kojic acid at one-tenth the concentration. The untreated oil managed only 2.1 percent inhibition, and the asarinin-rich oil an intermediate 49.3 percent. The pattern pointed squarely at sesamol as the active principle, consistent with earlier work showing sesamol is a potent monophenolase inhibitor with an IC50 of 3.2 micromolar, far exceeding kojic acid’s 59.72 micromolar, while sesamin and sesamolin lack inhibitory activity against the enzyme.

Molecular docking offered a structural explanation. Using a predicted structure of human tyrosinase, the researchers found that sesamol binds in the hydrophobic catalytic cavity with a favorable energy of minus 5.9 kilocalories per mole, close to arbutin’s minus 6.2. More tellingly, sesamol’s phenolic hydroxyl formed a hydrogen bond with Ser375, and its aromatic ring engaged in pi-stacking with His367, while making additional contacts with His180, His202, and His363. Those histidines are not incidental: they coordinate the binuclear copper center that drives tyrosinase’s catalytic chemistry. Sesamol thus appears to jam the enzyme by perturbing the microenvironment of its dicopper active site, occupying a different subsite from arbutin and raising the possibility of cooperative binding between the two inhibitors.

To test whether the effect survives in a living organism, the team turned to zebrafish embryos, a favorite screening platform for anti-melanogenesis compounds because their optical transparency allows pigment deposition to be watched in real time and their melanin synthesis pathways closely mirror those of humans. After establishing a maximum tolerated concentration of 1 milligram per milliliter, the researchers treated embryos for 45 hours. The sesamol-rich oil reduced cephalic melanin signal by 39.04 percent, approaching the 49.34 percent achieved by the positive control arbutin at five times the concentration. Biochemical assays confirmed the mechanism: melanin protein content fell to 60.35 percent of control levels and tyrosinase activity to 64.55 percent, closely matching the visible depigmentation.

The wound-repair experiments revealed a different division of labor. In a zebrafish skin injury model created by injecting acetic acid into larvae, all three oils accelerated healing, with efficacies of 56 percent for the untreated and sesamol-rich oils and 63 percent for the asarinin-rich oil at 100 milligrams per milliliter, approaching the 69 percent of epidermal growth factor. In a tail fin amputation model, however, the asarinin-rich oil pulled decisively ahead: at 25 milligrams per milliliter it achieved 39 percent tissue regeneration, roughly 44 percent better than the sesamol-rich oil and 56 percent better than untreated oil, nearing the performance of the positive control glycoin.

Anti-inflammatory activity told the opposite story. Using transgenic zebrafish whose neutrophils glow green, the researchers tracked the resolution of inflammation at amputated tail fins, where lingering neutrophils can release toxic granules that damage tissue. At low doses of 5 and 10 milligrams per milliliter, the sesamol-rich oil cleared 56 to 57 percent of wound-site neutrophils, dramatically outperforming both the untreated oil at 34 to 36 percent and the asarinin-rich oil at 37 to 38 percent, and beating the positive control dipotassium glycyrrhizinate’s 39 percent. At 25 milligrams per milliliter the asarinin-rich oil caught up, reaching 66 percent clearance. The authors attribute these divergent profiles to the lignan chemistry: sesamol is a known suppressor of reactive oxygen species and of pro-inflammatory cytokines such as IL-1 beta, IL-6, and TNF-alpha, while asarinin has been reported to inhibit superoxide-driven inflammatory activation more potently than sesamin.

The study’s broader significance lies in its demonstration that processing chemistry, not just the source plant, determines what a functional oil can do. Because the fatty acid matrix stayed constant while lignan composition was deliberately reshaped, the researchers could attribute specific bioactivities to specific lignan enrichments, effectively converting a traditional edible oil into a tunable platform for dermocosmetic design. The authors caution that the differential effects cannot yet be pinned on single compounds, since each oil retains a mixture of lignans and minor constituents, and the lipid matrix itself may influence lignan delivery and bioavailability. They also note that the sesamol-rich oil’s UV absorption at 287 nanometers was 14.4 percent higher than untreated oil, hinting at modest photoprotective value that requires verification in finished formulations. Still, with kojic acid associated with contact dermatitis and sensitization in some users, an edible-oil-derived alternative that approaches its tyrosinase-blocking potency while simultaneously offering wound-repair and anti-inflammatory benefits represents an appealing prospect for the next generation of natural skincare ingredients.

Subject of Research: Lignan-enriched sesame oils for skin lightening and wound repair

Article Title: Exploring the Potential of Sesamol/Asarinin-Enriched Sesame Oil in Skin Lightening and Wound Repair

Article References: Luo, Y.-Q., Li, Z.-Q., Wang, Q., Qin, J.-W., Yu, T., Liu, H.-M., & Yang, J.-C. (2026). Exploring the Potential of Sesamol/Asarinin-Enriched Sesame Oil in Skin Lightening and Wound Repair. Journal of Agriculture and Food Research, Article 103348. https://doi.org/10.1016/j.jafr.2026.103348

Image Credits: AI Generated

DOI: 10.1016/j.jafr.2026.103348

Keywords: sesame oil, sesamol, asarinin, tyrosinase, melanin, skin lightening, wound healing, zebrafish, lignans, cosmetics, anti-inflammatory, molecular docking