Question:
Secondary photosensitization occurs after the ingestion of
Secondary photosensitization occurs after the ingestion of
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Primary photosensitization: Pigment is directly absorbed from the plant (*Hypericum*, *Fagopyrum*).
Secondary photosensitization: Liver damage (*Lantana*, *Senecio*) $\rightarrow$ Failure to excrete phylloerythrin (ruminal chlorophyll metabolite).
Secondary photosensitization: Liver damage (*Lantana*, *Senecio*) $\rightarrow$ Failure to excrete phylloerythrin (ruminal chlorophyll metabolite).
Updated On: Jul 14, 2026
- Parthenium hysterophorus
- Fagopyrum esculentum
- Hypericum perforatum
- Lantana camara
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The Correct Option is D
Solution and Explanation
Step 1: Understanding the Concept:
Photosensitization is classified into:
- Primary Photosensitization: Ingested pre-formed photodynamic agents (like hypericin) reach the skin and cause damage.
- Secondary (Hepatogenous) Photosensitization: Liver damage prevents the excretion of phylloerythrin (a breakdown product of chlorophyll), which then accumulates in the skin and acts as a photodynamic agent.
Detailed Explanation:
Let us evaluate each plant:
- Hypericum perforatum (St. John's Wort) contains hypericin, a photodynamic pigment that directly causes primary photosensitization.
- Fagopyrum esculentum (Buckwheat) contains fagopyrin, causing primary photosensitization.
- Lantana camara contains toxic pentacyclic triterpene acids (lantadenes A and B).
Ingestion of Lantana causes severe intrahepatic cholestasis and hepatocellular damage in ruminants.
Due to this liver damage, the liver is unable to excrete phylloerythrin, a metabolite of chlorophyll produced by rumen microbes.
Phylloerythrin accumulates in the blood circulation and deposits in unpigmented skin areas, where exposure to sunlight triggers a photodynamic reaction, leading to tissue necrosis.
This process is the definition of secondary (hepatogenous) photosensitization.
Step 2: Final Answer:
Secondary photosensitization occurs after the ingestion of Lantana camara.
Photosensitization is classified into:
- Primary Photosensitization: Ingested pre-formed photodynamic agents (like hypericin) reach the skin and cause damage.
- Secondary (Hepatogenous) Photosensitization: Liver damage prevents the excretion of phylloerythrin (a breakdown product of chlorophyll), which then accumulates in the skin and acts as a photodynamic agent.
Detailed Explanation:
Let us evaluate each plant:
- Hypericum perforatum (St. John's Wort) contains hypericin, a photodynamic pigment that directly causes primary photosensitization.
- Fagopyrum esculentum (Buckwheat) contains fagopyrin, causing primary photosensitization.
- Lantana camara contains toxic pentacyclic triterpene acids (lantadenes A and B).
Ingestion of Lantana causes severe intrahepatic cholestasis and hepatocellular damage in ruminants.
Due to this liver damage, the liver is unable to excrete phylloerythrin, a metabolite of chlorophyll produced by rumen microbes.
Phylloerythrin accumulates in the blood circulation and deposits in unpigmented skin areas, where exposure to sunlight triggers a photodynamic reaction, leading to tissue necrosis.
This process is the definition of secondary (hepatogenous) photosensitization.
Step 2: Final Answer:
Secondary photosensitization occurs after the ingestion of Lantana camara.
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