More anthraquinone derivatives (140-142) were reported recently from the marine fungus Alternaria tenuissima DFFSCS013 . Anthrininone A (140) demonstrated selective protein tyrosine phosphatase inhibitory effect on indoleamine 2,3 dioxygenase 1 enzyme (IDO1) with IC50 value of 32.3 μM as well as the stimulatory effect on the intracellular levels of calcium in HEK293 cells at a concentration of 10.0 μM . It is noteworthy that 6-O-methylalaternin (141) displayed a wide range of anti-protein tyrosine phosphatases activity including activity against TCPTP, SHP1, SHP2, and PTP-MEG2 enzymes with potent bioactivity against both IDO1 and PTP1B with IC50 values of 1.7 and 2.1 μM, respectively. On the other hand, 141 did not show a noticeable stimulatory effect on the intracellular levels of calcium in HEK293 cells at a concentration of 10.0 μM , (Figure ). anti-acetylcholinesterase activity at a concentration of 100 μM . Interestingly, pachybasin (147) also demonstrated potent cytotoxic activity against the human cancer cell lines, KB and KBv200 with IC50 values of 3.17 and 3.21 μM, respectively . In addition, its derivative, ωhydroxypachybasin (149) as well as (+)-2'S-isorhodoptilometrin (148) exhibited significant cytotoxic activity against Hep-G2 and HeLa cancer cell lines showing IC50 value of 9.39, 22.6 μM, respectively . Also, compounds 148 and 149 revealed moderate DNA Topo I inhibitory activity with an IC50 value of 100.0, 50.0 μM, respectively, in addition to significant selective antibacterial activity against the Gram-positive bacterium, S. aureus showing MIC value of 25.0, 25.0 μM, respectively .