Table 3.

Proposed brine shrimp lethality assay (BSLA) toxicity classification scheme based on LC₅₀ values.

LC50 Value (μg/mL)	Toxicity	Rationale
LC50 ≤ 12	highly toxic	Similar to or higher toxicity than potassium dichromate control (LC50 = 12.24 μg/mL in this study, rounded off to 12 μg/mL for simplicity)
12 < LC50 ≤ 100	moderately toxic	Parallels classification in other schemes
100 < LC50 ≤ 500	mildly toxic	Non-toxic in some schemes [199,200], moderately toxic in others [197,198]; includes some vegetables and Vitex negundo leaf, which has preparations approved by the Philippine FDA as over-the-counter cough and asthma medication based on clinical studies for safety and efficacy
500 < LC50	essentially non-toxic	Includes some common vegetables; in preliminary screens for drug discovery purposes, where toxicity is used as a surrogate marker for other bioactivities, this category is often considered as sufficiently toxic for further study as a drug candidate if LC50 < 1000 μg/mL [22]