Table 2.

Effect of various physico-chemical treatments on anti-HIV-1 (III_B) activity of Sukumo extract in MT-4

Treated with	Compounda (EC50 μg/ml)
	Sukumo extract	Heparin	Dextran sulfate (MW 500,000)
Untreated	0.5891	8.2095	0.7016
121 °C 20 min	0.5166	NDf	NDf
Trypsinb	0.6686	ND	ND
Proteinase Kb	0.5727	ND	ND
Pronaseb	0.4736	ND	ND
NaOHc	1.0954	ND	ND
NaIO4d	0.5832	ND	ND
H2SO4 treatede	0.4155	>940	ND
HCl treatede	0.7707	ND	>1000

^aThe 50% effective concentration was determined by MTT assay using HIV-1 (III_B) strain and MT-4 cells.

^bThe Sukumo extract was digested by trypsin (Sigma) (0.5–1 mg/ml at a final concentration), proteinase K (100 ng/ml) and pronase (Fluka) (0.2 mg/ml) at 37 °C for 30 h. The digestions were terminated by boiling the solution for 20 min at 100 °C.

^cThe Sukumo extract was boiled at 100 °C for 6 h in the presence of 1N NaOH.

^dThe Sukumo extract was incubated at 4 °C for 40 h in the presence of 100 mM NaIO₄. After treatment, the Sukumo extract was precipitated with 2 volumes of ethanol and resuspended in 1 volume of H₂O.

^eEach compound was boiled at 100 °C for 6 h in the presence of 6N H₂SO₄ or for 2 h in the presence of 1N HCl. After treatment, pH was adjusted to 7.5.

^fND: not determined.