IDENTIFICATION
Common name: Validamycin
Iupac name: 1L-(1,3,4/2,6)-2,3-dihydroxy 6 hydroxymethyl-4-[(1S,4R, 5S,6S)-4,5,6 -trihydroxy-3-hydroxymethylcyclohex-2-enylamino]cyclohexylβ-D-glucopyranoside
Chemical abstracts name: [1S-(lα,4α,5β,6α)]-1,5,6-trideoxy-4-O-β-D-glucopyranosyl-5-(hydroxymethyl)-l-[[4,5,6-trihydroxy-3-(hydroxymethyl)-2 –cyclohexen-1-yl]amino]-D-chiro-inositol
Type: Fungicide
CAS RN: [37248-47-8]
M.F.: C20H35NO13
Mol Wt: 497.5
PHYSICAL CHEMISTRY
Form (appearance): Colourless, odourless, hygroscopic powder.
M.P.: 130-135℃ (decomp.)
V.P.: Negligible at room temperature
Solubility.: Readily soluble in water. Soluble in methanol, dimethylformamide and dimethyl sulfoxide Slightly soluble in ethanol and acetone. Sparingly soluble in diethyl ether and ethyl acetate.
Stability: Stable at room temperature in neutral or alkaline media, but slightly unstable in acidic media. / Specific rotation [α]24D＋1100 (water)
APPLICATION
Formulation types: DP; DS; SL; Liquid.
Biochemistry: Inhibitor of trehalase, an enzyme which mediates the digestion of the carbohydrate trehalose and transport of glucose to the hyphals tips.
Mode of action: Non-systemic antibiotic with fungistatic action. Causes abnormal branching of the tips of the pathogen, followed by cessation of further development.
Uses: Control of Rhizoctonia solani in rice, potatoc vegetables, strawberries, tobacco, ginger and other crops; damping off diseases of cotton, rice and sugar beet, etc. Applied as a foliar spray, soil drench, seed dressing, or by soil incorporation, at 1.25-1.56 g/ha (liquid), 9-12 g/ha (DL formulation), and 0.090 mg/kg (DL or seed dressing).
MAMMALIAN TOXICOLOGY
Oral: Acute oral LD50 for rats and mice >20000 mg/kg.
Skin and eye: Acute percutaneous LD50 for rats >5000 mg/kg. Non-irritating to skin (rabbits). Nota skin sensitiser (guinea pigs).
Inhalation: LC50 (4 h) for rats >5 mg/l air.
Noel: In 90 d feeding trials, rats receiving 1000 mg/kg diet and mice receiving 2000 mg/kg diet showed no ill-effects. In 2 y feeding trials, NOEL for rats was 40.4 mg/kg b.w. daily.
Toxicity: WHO (a.i.) III (Table 5); EPA (formulation) IV
ECOTOXICOLOGY
Fish: LC50 (72 h) for carp >40 mg/l.
Daphnia: LC50 (24 h) for D. pulex >40 mg/l.
ENVIRONMENTAL FATE
Animals: In animals, cleavage to glucose and an amine residue occurs.
Soil/Environment: Rapid microbial degradation in soil; DT50 ≤5 h.
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