The lichen host, Amandinea medusulina, collected from mangrove habitats in Sri Lanka, and its associated endolichenic fungi were isolated and identified by rDNA-ITS sequence analysis and morphological features. One of the fungal strains frequently isolated from the lichen thalli was identified as Xylaria psidii. This study aimed at the isolation and identification of the cytotoxic compounds present in this fungus. Secondary metabolites of X. psidii were first extracted into ethyl acetate and subsequently subjected to bioassay-guided fractionation to isolate the bioactive compounds. Sulforhodamine B assay against a lung cancer (NCI-H292) cell line was used to determine the differential cytotoxic activity. Bioassay-guided fractionation led to the isolation of an active compound, SS/02/29/08, showing moderate cytotoxicity (IC₅₀ = 27.2 µg/mL). Its structure was elucidated by IR, 1D- and 2D-NMR, and ¹³C-NMR spectrophotometry and MS, in combination with HRMS, ¹³C NMR, HSQC, HMBC, and DQF-COSY. The structure of SS/02/29/08 was determined as (Z)-3-{(3-acetyl-2-hydroxyphenyl)diazenyl}-2,4-dihydroxybenzaldehyde and identified as a new compound. This novel compound has promising differential cytotoxic activity against human lung cancer cell line (NCI-H292).

从斯里兰卡的红树林栖息地收集的地衣寄主Amandinea medusulina及其相关的苔藓内真菌通过rDNA-ITS序列分析和形态特征进行分离和鉴定。经常从地衣藻中分离出的一种真菌菌株被鉴定为Xylaria psidii。这项研究旨在分离和鉴定这种真菌中存在的细胞毒性化合物。X. psidii的次生代谢产物首先将其萃取到乙酸乙酯中，然后进行生物测定指导的分离，以分离出生物活性化合物。针对肺癌（NCI-H292）细胞系的磺胺多巴胺B测定用于确定差异的细胞毒活性。生物测定指导的分离导致了活性化合物SS / 02/29/08的分离，显示出中等的细胞毒性（IC ₅₀ = 27.2 µg / mL）。通过IR，1D和2D-NMR，¹³ C-NMR分光光度法和MS结合HRMS，¹³ C NMR，HSQC，HMBC和DQF-COSY阐明了其结构。SS / 02/29/08的结构确定为（Z）-3-{（3-乙酰基-2-羟基苯基）二氮杂基} -2,4-二羟基苯甲醛并被鉴定为新化合物。这种新化合物具有针对人肺癌细胞系（NCI-H292）的有希望的差异细胞毒活性。