Diketopiperazine and isoindolinone alkaloids from the endophytic fungus Aspergillus sp. HAB10R12.

Four previously undescribed alkaloids, aspergillinine A-D, and four known diterpene pyrones were isolated from the potato dextrose agar (PDA) culture of Aspergillus sp. HAB10R12. The chemical structures of the isolated compounds were elucidated based on a detailed analysis of their NMR and MS data.

Asperginols A and B, Diterpene Pyrones, from an sp. and the Structure Revision of Previously Reported Analogues.

Two new diterpene pyrones, asperginols A () and B (), and four known analogues (-) were isolated from the endophytic fungus sp. HAB10R12. The structures and absolute configurations of these compounds were elucidated based on the analysis of their NMR, MS, and X-ray diffraction data.

Food additive "lauric acid" possess non-toxic profile on biochemical, haematological and histopathological studies in female Sprague Dawley (SD) rats.

Background: Lauric acid (LA), a common constituent of coconut oil, is used as food additives and supplements in various formulations. Despite various potential pharmacological properties, no scientific evidence on its dose-related toxicity and safety is available till date.

Objective: The current study was conducted to evaluate acute oral toxicity of LA on normal rats.

Natural diterpene pyrones: chemistry and biology.

Diterpene pyrones (DTPs) are a group of well-known, mainly fungal, natural products, first isolated in 1966. As the name indicates, they are composed of two main structural features: a diterpenyl moiety and a pyrone ring. Various names have been given to this class of metabolites; however, biogenetic evidence indicates that they originate through the same metabolic pathway.

Ethyl 4-(2-hydroxy-ethyl-amino)-3-nitro-benzoate.

In the title compound, C(11)H(14)N(2)O(5), the mol-ecular structure is stabilized by an intra-molecular N-H⋯O hydrogen bond, which generates an S(6) ring motif. The nitro group is twisted slightly from the attached benzene ring, forming a dihedral angle of 5.2 (2)°.

4-Butyl-amino-3-nitro-benzoic acid.

The asymmetric unit of the title compound, C(11)H(14)N(2)O(4), comprises four crystallographically independent mol-ecules (A, B, C and D) with similar geometries. In each mol-ecule, the butyl-amino side chain is in an extended conformation, and the carboxyl and butyl-amino groups are almost coplanar with the attached benzene ring; the nitro group is slightly twisted away from the benzene ring. In the asymmetric unit, the benzene rings of mol-ecules A, B and C are stacked parallel to one another, with a centroid-centroid distance of 3.

4-Ethyl-amino-3-nitro-benzoic acid.

In the title compound, C(9)H(10)N(2)O(4), an intra-molecular N-H⋯O hydrogen-bond inter-action generates an S(6) ring motif. The nitro group is slightly twisted away from its attached benzene ring [dihedral angle = 15.29 (15)°].

4-tert-Butyl-amino-3-nitro-benzoic acid.

In the title compound, C(11)H(14)N(2)O(4), all non-H atoms lie in a mirror plane except for one of the methyl groups which deviates from the mirror plane by 0.919 (3) Å and is twisted by a torsion angle of 62.9 (2)°.

4-Cyclo-butyl-amino-3-nitro-benzoic acid.

The asymmetric unit of the title compound, C(11)H(12)N(2)O(4), contains two crystallographically independent mol-ecules with similar geometries. Both mol-ecules contain an intra-molecular N-H⋯O hydrogen bond. The dihedral angles between the benzene ring and the mean plane of the cyclo-butane ring are 38.

4-(But-3-enylamino)-3-nitro-benzoic acid.

The asymmetric unit of the title compound, C(11)H(12)N(2)O(4), contains 12 crystallographically independent mol-ecules, labelled A to L. The nitro and carboxyl groups are twisted slightly out of the plane of the attached benzene ring in all independent mol-ecules except mol-ecules G and D. The nitro group is coplanar with the benzene ring in mol-ecule G and the carboxyl group is coplanar with the benzene ring in mol-ecule D.

4-(sec-Butyl-amino)-3-nitro-benzoic acid.

The asymmetric unit of title compound, C(11)H(14)N(2)O(4), consists of two crystallographically independent mol-ecules (A and B). In each, intra-molecular N-H⋯O hydrogen bonds generate S(6) ring motifs. The mean plane of the nitro group forms dihedral angles of 4.

Ethyl 4-fluoro-3-nitro-benzoate.

In the title compound, C(9)H(8)FNO(4), C-H⋯O inter-molecular inter-actions form dimers with R(2) (2)(10) motifs. These dimers are arranged into chains parallel to the b axis and the chains are stacked down the c axis.

Ethyl 4-butyl-amino-3-nitro-benzoate.

In the crystal structure of the title compound, C(13)H(18)N(2)O(4), the asymmetric unit consists of three crystallographically independent ethyl 4-butyl-amino-3-nitro-benzoate mol-ecules. There is an intra-molecular N-H⋯O hydrogen bond in each mol-ecule, which generates an S(6) ring motif. The structure is stabilized by inter-molecular N-H⋯O and C-H⋯O hydrogen bonds.