Table 2.
Laboratory efficacy score for in vitro antiplasmodial activity of crude extracts
| IC50 (μg/ml) (best**) | Score | Level of activity |
|---|---|---|
| Not tested | 0 | Needs to be tested (priority to be determined according to other criteria) |
| < 2.0 | +10* | Very good |
| 2.0 - 5.0 | +5* | Good |
| This is the concentration range that is generally considered as active in screening programmes for anti-malarial activity, warranting bioassay-guided fractionation. | ||
| 5.1 - 10 | +3* | Good to moderate |
| This range may reasonably be considered for bioassay-guided fractionation. | ||
| 11 - 25 | +2* | Weak |
| 26 - 50 | +1 | Very weak |
| >100 | -2 | Inactive |
** Aqueous extracts were priopritized but if these were not available, results from ethanolic extracts or methanolic extracts were used. Results from non-polar extracts such as dichloromethane and petroleum ether are too far removed from traditional preparations and were excluded.
*Add +1 if this level of activity is confirmed in more than one strain of P. falciparum, from a different continent or with different drug sensitivity, and +2 if confirmed in 2 or more strains.