Kan Jang - does andrographis paniculata gang up on respiratory-infection bugs?

Endurance athletes engaged in very strenuous training are at increased risk of respiratory-system infections, and these infections can limit training and thus retard gains in fitness. For years, athletes and exercise scientists have searched for ways to keep these training-related infections at bay.
Recently, sports nutritionists have suggested that a herb called Andrographis paniculata (aka Kan Jang) possesses anti-inflammatory and immune-system-boosting activity. The popular press has suggested that Andrographis is the 'latest herb discovery' and might be more effective than Echinacea against cold and flu symptoms.
Is there anything in this? For the ingredients in a herbal supplement to be physiologically active, they must first pass readily across the wall of the small intestine and be taken up by the blood, which will then whisk the ingredients to various parts of the body. In a recent study carried out by researchers at the Guelbenkian Research and Drug-Quality-Control Laboratory of ADMTA in Yerevan, Armenia (you may communicate with the investigators at phanos@sci.am), both rats and human volunteers orally ingested Andrographis paniculata ('Pharmacokinetic and Oral Bioavailability of Andrographolide from Andrographis paniculata Fixed Combination Kan Jang in Rats and Humans,' Phytomedicine, Vol. 7(5), pp. 351-364, October 2000). The Armenian researchers discovered that the apparently key ingredient in Andrographis paniculata - a compound called andrographolide - was quickly and almost completely absorbed into the bloodstreams of rats following the oral administration of Andrographis paniculata extract at a dose of 20 mg/kg body weight. Rapid urinary excretion of andrographolide did not appear to be a problem.
A similar scenario unfolded in human subjects, with blood-plasma levels of andrographolide reaching maximal levels about 1.5 to two hours after ingestion of the supplement; about half the absorbed andrographolide was still in the blood nearly seven hours after ingestion. To achieve an anti-platelet-activating-factor effect (more on this in a moment), the Armenian researchers suggested a therapeutic dose regimen of about one milligram of andrographolide per kilogram of body weight per day, perhaps spaced out in three separate dosages.

Does it work?
To determine whether Kan Jang can really hang up the progression of colds, researchers at the Hallehalsan Clinic in Ulricehamn, Sweden (communicate with scientists at jan.melchior@swipnet.se) recently carried out two randomised, double-blind, placebo-controlled clinical trials with a total of 225 patients suffering from uncomplicated upper-respiratory-tract infections (Double-blind, Placebo-controlled Pilot and Phase III Study of Activity of Standardised Andrographis paniculata Herba Nees Extract Fixed Combination (Kan Jang) in the Treatment of Uncomplicated Upper-respiratory Tract Infection, Phytomedicine, Vol. 7(5), pp. 341-350, October 2000).
46 subjects took part in a pilot study carried out by the Swedes, and 179 patients participated in follow-up work. Andrographis paniculata was taken three times daily for a minimum of three days and a maximum of eight days during the pilot study, and for exactly three days in the second investigation. The primary outcome measures in the patients' self-evaluations were muscle pain, extent of coughing, throat discomfort, headache, nasal symptoms, eye irritations, and body temperature. The physicians' fixed-score diagnoses were based mainly on the patients' signs and symptoms associated with the ears, nose, eyes, oral cavity, lymph glands, and tonsils. Total symptom scores showed a moderate tendency toward improvement with Kan-Jang use in the pilot study, while in the follow-up investigation both the total symptom score and total diagnosis score showed highly significant improvement for Andrographis-paniculata users, compared with the placebo group. The throat was the area of the body most influenced by Andrographis-paniculata ingestion; in both studies throat signs and symptoms showed the most significant improvement.
How might Andrographis paniculata actually work? The mechanisms are not yet clear, but it is believed that andrographolide is antagonistic to something called platelet-activating factor (PAF). Platelets are small components of the blood involved in clotting and immune-system activities, and PAF can spur inflammation in response to infection.