Two new metabolites, diorcinolic acid (1) and β-D-glucopyranosyl aspergillusene A (8), together with six diphenylethers (2-7), a diketopiperazine (9), a chromone (10) and a xanthone (11) were isolated from the fungus Aspergillus sydowii derived from the marine sponge Stelletta sp. The planar structures and their relative configurations were elucidated by analysing 1D, 2D NMR and HRESIMS data. Compound 8 is the first glycoside of phenolic bisabolane sesquiterpenes. Compounds 1 and 8 exhibited mild cytotoxicity against KB (human nasopharyngeal carcinoma cells), HepG2 (human liver cancer cells) and HCT 116 (human colon cancer cells). All compounds were evaluated for antibacterial activity and their abilities to suppress LPS-induced nitric oxide (NO) production. Compounds 2 and 4-7 showed mild antibacterial activity against human pathogen Staphylococcus aureus and fish pathogens Streptococcus iniae and Vibrio ichthyoenteri, and compounds 4 and 7 weakly suppressed NO production.

cytotoxicity, antibacterial activity, sesquiterpene glycoside, Aspergillus sydowii, Marine fungus, diphenylether, no suppression

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6	C7	C8	C9	C10	C11	C12	C13	C14	C15
15	bDGlcp	100.4	73.9	76.9	70.2	77.3	61.4
	Subst	154.5	134.8	129.4	120.4	141.3	113.4	134.7	129.9	26.0	38.7	27.8	21.8	21.8	16.5	63.9


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6	H7	H8	H9	H10	H11	H12	H13	H14	H15
15	bDGlcp	5.00	3.45	3.42	3.38	3.44	3.90
	Subst	-	-	7.02	6.94	-	7.10	-	5.37	2.16	1.33	1.60	0.94	0.94	2.00	4.55


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6	C7/H7	C8/H8	C9/H9	C10/H10	C11/H11	C12/H12	C13/H13	C14/H14	C15/H15
15	bDGlcp	100.4/5.00	73.9/3.45	76.9/3.42	70.2/3.38	77.3/3.44	61.4/3.90
	Subst			129.4/7.02	120.4/6.94		113.4/7.10		129.9/5.37	26.0/2.16	38.7/1.33	27.8/1.60	21.8/0.94	21.8/0.94	16.5/2.00	63.9/4.55

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

C/C(=C\CCC(C)C)c1ccc(CO[C@@H]2O[C@H](CO)[C@@H](O)[C@H](O)[C@H]2O)cc1O

396.48 g/mol (C₂₁H₃₂O₇)