Three new limonoids, limonophyllines A-C (1, 4 and 5), along with two known limonoids (2 and 3) and 11 acridone alkaloids (6-16) were isolated from the stems of Atalantia monophylla. All isolates were evaluated against cholangiocarcinoma, KKU-M156, and HepG2 cancer cell lines. Compounds 12, 14 and 16 displayed cytotoxicity against KKU-M156 cell line with IC ranging from 3.39 to 4.1 μg/mL while cytotoxicity against HepG2 cell line with IC ranging from 1.43 to 8.4 μg/mL. The structures of all isolated compounds were established by spectroscopic methods including 1D and 2D NMR, IR and mass spectrometry.

Four new benzoyltyramines, atalantums H-K (1-4) and seven known compounds were isolated from the peels of Atalantia monophylla. All compounds were tested for cytotoxicity against HeLa, HCT116 and MCF-7 cell lines, as well as normal cells (Vero cells). Compound 5 showed cytotoxicity against HeLa, HCT116 and MCF-7 cell lines with IC 50 values ranging from 16-25 g/mL but was inactive against Vero cells. Compound 6 also showed interesting results as compound 5 with IC 50 values ranging from 15-18 g/mL and an IC 50 value of 80.20 g/mL against Vero cells. This means compounds 5 and 6 can be used as lead compounds for anticancer agents.

Four new dimeric styrenes, 1−4, were isolated from an EtOAc crude extract of the seeds of Atalantia monophylla. The biosynthetic pathway of 1 is proposed to involve a [2 + 2] cycloaddition, while 2−4 may be generated via a polar mechanism with a carbocation as the key intermediate. The structures of 1−4 were defined from spectroscopic analysis; experimental and calculated ECD spectra were used to characterize their absolute configurations. When tested against two different cancer cell lines, 1−4 were not determined to be cytotoxic (IC 50 > 10 μM).Atalantia monophylla (L.) DC., a species of plant in the family Rutaceae, 1,2 is found throughout India, Sri Lanka, and Southeast Asia and is known as "Ma Nao Phee" in Thai. 3 This medicinal plant has been used in folklore medicine for various purposes. 4,5 The leaves of this plant are used to treat itching and other skin ailments. 6 In turn, the oil from its fruits has been used for paralytic limbs and chronic rheumatism, while the roots have been used as an antispasmodic. 7−9 In previous work, seven new benzoyltyramine alkaloids (atalantums A−G) and five known derivatives were found in the peel of this plant. 10 As a continuation of studies on this plant, several compounds were isolated and identified, and their cytotoxic effects were tested against cholangiocarcinoma and hepatoma cell lines.Cholangiocarcinoma (CCA) is the most serious type of cancer in the northeast region of Thailand. 11 Infection by Opisthorchis viverrini, an endemic liver fluke that is commonly found in some types of freshwater fish, causes this disease. 12 A potentially curative therapy for the disease is surgical resection. 13 However, the poor prognosis for this tumor type leads to more than half of patients developing advanced CCA, 14,15 representing a type of unresectable malignancy. In addition, there is no effective anticancer drug for treating the disease. Thus, the development of effective therapeutic agents, especially from medicinal plants that display promising effects for the treatment of this type of cancer, is of great interest.

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