MF: C₄₄H₆₈O₁₃
Density: 1.28 g/cm³
MW: 805.002920 g/mol
Flash Point: 269.4 °C
Storage temp: −20°C
Solubility: DMSO: ≥1 mg/mL
Appearance: translucent film
Index of Refraction: 1.584 
Melting Point: 164-166 °C
Vapour Pressure: 0 mmHg at 25°C   
Enthalpy of Vaporization: 152.12 kJ/mol 
Boiling Point: 921.6 °C at 760 mmHg
Appearance: white crystals or powder
Stability: Stable. Light and heat-sensitive. Combustible. Incompatible with strong oxidizing agents.  
IUPAC Name: (2R)-3-[(2S,6R,8S,11R)-2-[(E,2R)-4-[(2S,2'R,4R,6R,8aR)-4-hydroxy-2-[(1S,3S)-1-hydroxy-3-[(3R,6S)-3-methyl-1,7-dioxaspiro[5.5]undecan-2-yl]butyl]-3-methylidenespiro[4a,7,8,8a-tetrahydro-4H-pyrano[3,2-b]pyran-6,5'-oxolane]-2'-yl]but-3-en-2-yl]-11-hydroxy-4-methyl-1,7-dioxaspiro[5.5]undec-4-en-8-yl]-2-hydroxy-2-methylpropanoic acid
Synonyms: OA ; Okadaic acid, prorocentrum concavum ; Okadaic acid ; 9,10-Deepithio-9,10-didehydroacanthifolicin ; 9,10-Deepithio-9,10-didehydroacanthiofolicin ; Halochondrine a ; 9,10-Deepithio-9,10-didehydro-acanthifolici ; Okadaic acid >95% protein phosphatase i
Following is the molecular structure of Okadaic acid (78111-17-8):

A poison by intraperitoneal route. Questionable carcinogen. Mutation data reported. When heated to decomposition it emits acrid smoke and irritating vapors.
Safety Information
Hazard Codes: T
T: Toxic
Risk Statements: 23/24/25-38
23/24/25: Toxic by inhalation, in contact with skin and if swallowed 
38: Irritating to the skin  
Safety Statements: 26-36/37-45
26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice
36/37: Wear suitable protective clothing and gloves 
45: In case of accident or if you feel unwell, seek medical advice immediately (show label where possible)  
RIDADR: UN 3462 6.1/PG 1
WGK Germany: 3
RTECS: AA8227800
F10: Keep under argon.
HazardClass: 6.1(a)
PackingGroup: II

 Okadaic acid (78111-17-8) is a toxin that accumulates in bivalves and causes diarrhetic shellfish poisoning. It was named from the marine sponge Halichondria okadai, from which okadaic acid was isolated for the first time. It has also been isolated from another marine sponge, H. malanodocia, as a cytotoxin. The real producer of okadaic acid is a marine dinoflagellate.
Administration of okadaic acid has been shown to profoundly increase the secretion of nerve growth factor, and to also promote nerve growth factor gene transcription and the stability of mRNA in primary cultures of cortical astrocytes.
The cytotoxicities of okadaic acid as EC50 against the P388 and L1210 cell lines are 1.7 nanomolar and 17 nanomolar, respectively. Additionally, okadaic acid strongly inhibits protein serine / threonine phosphatase 1, 2A, and 2B. The inhibitory effect of okadaic acid is strongest for 2A, followed by 1, and then 2B. The dissociation constant of the inhibition on protein serine / threonine phosphatase 2A is 30 pico-molar.