24Z-Masticadienonic acid (MNA) and 24Z-isomasticadienonic acid (IMNA) are the major triterpenic acids in Chios Mastic Gum (CMG), a resin derived from Pistacia lentiscus var. Chia. Despite their promising pharmacological potential, limited information is available due to the complexity of isolating them in pure form. This study developed a chemo-selective method for isolating MNA and IMNA and investigated their chemical transformation through isomerization of the external double bond and A-ring contraction of the triterpene scaffold. A rapid method for isolating MNA from CMG was first established, followed by a high-yield acid-catalyzed procedure to obtain both 24Z and 24E isomers of IMNA. Additionally, a basic catalyzed isomerization of IMNA led to the formation of two new compounds with A-ring contraction, which could serve as novel scaffolds for the design of new triterpene analogs. The mixture of MNA/IMNA, along with the individual compounds and their semi-synthetic analogs, exhibited significant anti-inflammatory activity. Notably, 24E-isomasticadienonic acid and 24Z-2-hydroxy-3-oxotirucalla-1,8,24-trien-26-oic acid, a previously unreported compound, significantly reduced the mRNA expression levels of Tnf, Il6, and Nfkb1 in RAW 264.7 macrophage cells.

Chios mastic gum (CMG), the resin of Pistacia lentiscus var. Chia, is a product with great ethnopharmacological and economic significance. This study attempts to investigate, for the first time, the activity of CMG, its fractions and isolated compounds against specific enzymes, which play pivotal roles in the degradation of proteins contained in skin connective tissue. Initially, crude CMG was subjected to extraction, fractionation and isolation through different chromatographic techniques to obtain the acidic and neutral fraction of terpenes. Additionally, the characteristic and major active triterpene acids of CMG, masticadienonic and isomasticadienonic acids (MNA, IMNA) were isolated in pure form. All samples were analysed by means of High-Performance Thin-Layer Chromatography (HPTLC) with four distinct development systems to obtain their constituents’ profile. Finally, samples were tested for their ability to inhibit the elastase and collagenase enzymes. According to our findings, for collagenase, a mixture of MNA and IMNA demonstrated the most potent activity with an IC₅₀ value of 31.07 μg/mL, while for elastase CMG’s acidic fraction provided the most promising results with an IC₅₀ value of 17.30 μg/mL. Overall, these results attempt to fill the gap in scientific knowledge about the use of CMG and its constituents in skincare and cosmetic products.

Τriterpenic acids represent a prominent class of bioactive compounds, with a wide range of biological properties, including anti-inflammatory, antiviral, and anticancer effects. Among them, 24Z-isomasticadienonic acid (IMNA), a major constituent of Chios Mastic Gum, has attracted little attention compared with other well-studied triterpenes such as oleanolic or betulinic acid, largely because its isolation in sufficient purity and quantity was only recently achieved. In this study, a series of IMNA analogs was synthesized through targeted modifications at the A-ring. These included the introduction of heteroatoms at position 2, the incorporation of heterocyclic rings such as an oxazole and a thiazole, and rearrangements of the ring structure. The new compounds were evaluated for their antiproliferative activity against a diverse panel of cancer cell lines (Capan-1, HCT-116, LN-229, NCI-H460, DND-41, HL-60, K-562, Z-138). Among the synthesized analogs, compounds 3, 7 and 9 demonstrated selective anticancer activity toward the Capan-1 cell line, whereas compounds 6 and 10 exhibited broad-spectrum cytotoxic effects across multiple cancer cell lines. Overall, these findings highlight IMNA as a promising scaffold for anticancer drug design and demonstrate the value of A-ring modifications in improving activity and selectivity.